June 2020

Notes: Unless otherwise indicated, the years referred to in this report are federal fiscal years, which run from October 1 to 

September 30 and are designated by the calendar year in which they end. All costs are expressed in 2021 dollars. Costs for years 

before 2021 have been adjusted for inflation with the gross domestic product price index from the Bureau of Economic Analysis.

Costs of Creating a Space National Guard

The National Defense Authorization Act for Fiscal Year 

2020 established the Space Force as a new, independent 

military service within the Department of the Air Force. 

Intended to conduct operations that involve space—such 

as maintaining satellites that are used for communications, 

observing the weather, and monitoring other countries’ 

missile launches—the Space Force is currently authorized 

to operate only with regular (active component) 

personnel. 

The creation of this new service has led to various proposals to establish a Space National Guard, which would 

supplement the Space Force’s active component forces 

as required. Such proposals have typically focused on 

existing units within the Air National Guard and Army 

National Guard that have space-related missions, including national space functions (such as missile warning and 

missile defense or space tracking) and deployable missions (primarily involving satellite communications). The 

Department of Defense (DoD) is studying the issue of 

whether to create a reserve component for the Space Force, 

either a Space National Guard or a Space Force Reserve, 

that would be similar to those of the other services.1

In this report, the Congressional Budget Office examines 

two options for establishing a Space National Guard 

that would support the Space Force. In its analysis, 

CBO focused on a smaller version of a prospective Space 

National Guard and a larger version, and estimated the 

1. Throughout this report, “reserve component” refers collectively 

to the nonactive component of the U.S. military, which 

encompasses the National Guard and reserves. 

additional costs beyond those incurred for existing units 

in the Air National Guard and Army National Guard 

that have space-related missions. Specifically: 

• CBO considered a smaller version of a Space National 

Guard that is based on a February 2020 proposal 

by senior National Guard personnel. Under that 

proposal, 1,500 personnel in existing Air National 

Guard and Army National Guard units would be 

transferred to the new Space National Guard. CBO 

estimates that DoD would incur about $100 million 

in additional costs annually to operate and support 

this smaller Space National Guard. Creation of such 

a force also would probably result in onetime costs of 

about $20 million for the construction of additional 

facilities.

• CBO also considered a larger version of a Space 

National Guard that would be about one-third 

the size of the Space Force, the same size that the 

Air National Guard currently is in relation to the 

Air Force. (Unlike the first option, this one is not 

based on a specific public proposal.) Under that 

approach, the Space National Guard would consist 

of 4,900 to 5,800 personnel. CBO estimates that 

DoD would incur $385 million to $490 million in 

additional costs annually to operate and support this 

larger Space National Guard. Creation of this larger 

force also would probably result in onetime costs 

of $400 million to $900 million for constructing 

additional facilities and equipping the new units.
2 Costs of Creating a Space National Guard June 2020

A reserve component to support the Space Force could 

be structured in other ways—including a Space Force 

Reserve that would operate exclusively at the federal 

level, rather than a National Guard that would allow for 

shared control between the federal government and states 

and territories. However, the costs of National Guard 

or reserve units would not differ significantly. The size 

of the reserve component would be the primary factor 

affecting costs.

Background

The creation of the Space Force has led to various proposals to create a Space National Guard. Those proposals 

have been influenced by the historical experience and 

organization of existing National Guard and reserve 

forces.

Creation of the Space Force

Enacted in December 2019, the National Defense 

Authorization Act for Fiscal Year 2020 (Public Law 116-92) 

established the Space Force as a new military service 

within the Department of the Air Force. That act did not 

create either a Space National Guard or a Space Force 

Reserve, so, at present, the Space Force has legal authority 

to operate only with active component (AC) military 

personnel.

DoD is still developing its plans to organize and equip 

the Space Force. In its budget request for fiscal year 

2021, the department indicates that the Space Force will 

consist of 6,400 military personnel in 2021 and grow 

to a force of 8,100 military personnel by 2025. At least 

in the short term, the Department of the Air Force will 

create the Space Force primarily by transferring existing 

Air Force organizations and units with space-related 

missions to the Space Force. Although there are units 

with space-related missions in the other military services, 

DoD has not yet issued a plan to transfer those units to 

the Space Force.

The most recent guidance detailing the Department of 

the Air Force’s plans for structuring the Space Force is 

described in a February 2020 report titled Comprehensive 

Plan for the Organizational Structure of the U.S. Space 

Force.

2

 That report indicates that the new service will 

depend on the Air Force for many support and overhead 

2. See Department of the Air Force, Comprehensive Plan for the 

Organizational Structure of the U.S. Space Force, Report to 

Congressional Committees (February 2020), https://tinyurl.com/

y9mm8zth (PDF, 824 KB).

functions (just as the Marine Corps depends on the Navy 

for such functions). The report does not include a plan 

for the organization of Space Force reserve component 

(RC) forces, stating that the matter would be addressed 

in a report to be issued in March 2020. The department 

has not yet issued that report.

History and Organization of National Guard and 

Reserve Forces

All U.S. armed services other than the Space Force have 

an active component and a reserve component. Each service’s RC includes a reserve (the Air Force Reserve, Army 

Reserve, Navy Reserve, and Marine Corps Reserve). The 

Air Force and the Army (but not the Navy or Marine 

Corps) also have National Guards (the Air National 

Guard and the Army National Guard). Thus, for example, the entire Army is composed of the regular Army, 

the Army Reserve, and the Army National Guard.

The primary difference between service reserves and 

National Guards is that reserves are organized as single 

entities wholly under federal government control (as 

provided by title 10 of the U.S. Code). By contrast, 

National Guards are organized on the basis of states and 

territories, with legal authorities that allow for hybrid 

state–territory and federal control (as provided by titles 

10 and 32 of the U.S. Code). Governors’ authorities 

extend only to Guard units within their respective state 

or territory: The governor of Texas, for example, may call 

up (activate) and command the Texas National Guard 

but not Guard forces from other states.3

Before the Vietnam War, RC forces were considered to 

represent additional increments of capability that could 

be maintained at relatively low cost in peacetime and 

then activated in times of conflict when active component forces were insufficient to deal with the military 

challenges (the “strategic reserve” model). The combination of very small AC ground forces during peacetime 

and this traditional view of reserves as providing additional increments of capability led the United States to 

rely heavily on RC units in military conflicts. During the 

Vietnam War, however, in a break from historical precedent, policymakers chose to limit reliance on RC forces.

3. All state National Guards are also part of the United States 

National Guard (which is administered by the National Guard 

Bureau). For example, the Army National Guard is part of both 

the Army and the United States National Guard. The same 

applies at the state level. For example, the Texas Army National 

Guard is part of both the Army and the Texas National Guard.
June 2020 Costs of Creating a Space National Guard 3

In the post–Vietnam War era, DoD has transitioned 

away from the strategic reserve model and instead 

operates under what is known as the Total Force Policy. 

Although each military service interprets this policy 

somewhat differently, the policy in general requires the 

services to integrate RC personnel and units into their 

plans by using such units when they are best able to meet 

needs or perform missions. That approach differs from 

simply assuming that AC personnel and units should be 

prioritized in all circumstances and RC units used only 

when AC capabilities are insufficient to meet needs or 

perform missions. Thus, DoD does not generally operate 

under the assumption that AC units will be the preferred 

response for every mission; for many missions, RC units, 

or a mix of AC and RC units, will be the preferred 

response or perhaps the only possible response.

For example, because RC units are generally less costly 

to sustain in peacetime than AC units, a Total Force 

approach will tend to emphasize maintaining in the RC 

capabilities (such as those provided by construction engineers) that are used only occasionally during peacetime, 

where they may be sustained at lower cost until needed. 

Similarly, because National Guard units are readily available for state and local missions, a Total Force approach 

will tend to emphasize sustaining units that are useful for 

state and local missions (such as transportation or utility 

helicopters) in the National Guard, where they will be 

more available for those missions.

Issues Raised by Historical Experience 

A Space Force RC could be organized in different ways. 

It could include a reserve that operates at the federal level 

like those of the other services. It also could include a 

National Guard like those of the Air Force and the Army. 

(Those are not exclusive—the Space Force could have 

both a National Guard and a reserve, which would mirror Air Force and Army practice.) Historical experience 

raises several issues for policymakers to consider: 

• Reserve units support U.S. forces in national 

missions. If RC units in the Space Force primarily 

or exclusively supported national missions (jamming 

satellite links in a theater, for example), a Space 

Reserve could allow them to do so without the 

additional organizational and legal complexities of a 

Space National Guard.

• National Guard units perform many state and local 

missions. If state and local missions related to space 

are expected to be important for RC units in the 

Space Force, transferring the current Air National 

Guard and Army National Guard units that conduct 

space missions to a Space National Guard—as 

outlined in the first option that CBO analyzed—

could allow them to do so.

• U.S. forces routinely employ joint commands and do 

not require units to be in the same service in order 

to employ them.4

 Leaving current space-related units 

where they are—in the Air National Guard and the 

Army National Guard—could still allow them to 

support the Space Force.

Costs of a Smaller Space National Guard

Various proposals for creating a Space National Guard 

have been made since the Administration announced 

its intention to seek authorization for a separate Space 

Force. The most prominent such proposal was presented 

in a February 12, 2020, briefing when senior leaders of 

the National Guard Bureau and several state adjutant 

generals proposed a plan to create a Space National 

Guard by converting existing Air and Army National 

Guard units with space-related missions into a new 

Space National Guard.5

Description

Under this proposal, roughly 1,500 personnel would be 

transferred from Air and Army National Guard units in 

seven states and one territory to a new Space National 

4. Some maintain that it would be unusual for one service to 

depend on another service for performing the organize, train, 

and equip (OTE) functions. However, the joint command 

arrangements are well codified and understood, and it is standard 

DoD practice to describe combat commanders—rather than 

a particular service—as the ultimate “customers” for whom 

the services perform OTE functions. Under that arrangement, 

whether units involved in space activities reside in the Space 

Force or the Air Force and the Army, they should be organized, 

trained, and equipped to support Space Command, the unified 

commander for space operations.

5. This proposal was widely reported. See, for example, Rachel 

S. Cohen, “Pentagon Mulls Space National Guard Options,” 

Air Force Magazine (February 12, 2020), https://tinyurl.com/

yakbvks5; Sandra Erwin, “National Guard Leaders Press Case 

for a Space National Guard,” Space News (February 12, 2020), 

https://tinyurl.com/spsnfym; and Valerie Insinna, “Does the 

Space Force Need a Guard Component? The National Guard 

Says Yes,” Defense News (February 14, 2020), https://tinyurl.com/

yb8zqrnc.
4 Costs of Creating a Space National Guard June 2020

Guard.6 Those units currently have space-related missions. The largest state National Guard contingent of 

those units is in the Colorado National Guard. Current 

Guard units include some with missions that support 

national space functions, such as missile warning and 

missle defense or space tracking (which, for instance, 

involves the monitoring of objects in space). Many of 

the other units include expeditionary (deployable) forces, 

primarily involving satellite communications—both 

protecting the ability of U.S. forces to rely on such communications and interfering with the ability of hostile 

forces to rely on such communications.

The argument for transferring those units is that doing so 

would accomplish the following:

• Simplify command arrangements (by allowing Space 

National Guard units to respond to the Space Force, 

rather than requiring Air National Guard units to 

respond to the Space Force); 

• Result in either no or modest additional costs 

(because the units already exist, are already funded, 

and have required infrastructure, facilities, and 

equipment in place); and 

• Allow for the straightforward creation of a reserve 

component for the Space Force that would preserve 

the benefits of RC units without extensive study or a 

lengthy implementation process.

Although not explicitly stated, such a proposal also 

would probably entail some other transfers: For example, transferring 1,500 personnel from currently existing 

units would suggest that a training pipeline of about 

50 to 90 personnel—depending on assumptions about 

additional overhead personnel—also would need to be 

transferred from existing National Guard personnel. (To 

maintain any given number of units, the services must 

maintain a flow of trainees that are being prepared to 

6. Public sources differ about the number of states involved, with 

reports of either seven or eight states engaged in such activities. 

The 2021 National Guard Bureau Posture Statement (available 

at https://tinyurl.com/ycvxwxb7) indicates that there are seven 

National Guard states (Alaska, California, Colorado, Florida, 

Hawaii, New York, and Ohio) and one territory (Guam) engaged 

in space-related operations (see page 34). Public sources generally 

agree that 1,100 of the proposed personnel would come from 

Air National Guard units; the remaining 400 would be drawn 

from Army National Guard units.

replace personnel in those units who leave the service, 

referred to as the training pipeline.)

A Space National Guard created in such a manner would 

be much smaller than other National Guards in absolute 

terms and smaller as a proportion of the total Space 

Force than the Air National Guard’s size in relation 

to the total Air Force. It also would be geographically 

restricted in scope to far fewer states and territories 

than other Guard forces (which are present in 50 states, 

3 territories, and the District of Columbia). The second 

option that CBO analyzed, which is discussed below, 

would involve a larger force and more states with Space 

National Guard units.

Costs

CBO estimates that creating a smaller Space National 

Guard would result in additional annual operation and 

support (O&S) costs totaling $100 million, along with 

onetime construction costs of $20 million.

It is unclear to what degree such a force would require 

additional administrative overhead—each state and 

territory that would be affected by the transfer already 

has a state organization to administer and command its 

National Guards, so moving units to the Space National 

Guard probably would not require many more overhead 

personnel to administer and command them. However, 

it is likely that a small number of additional personnel would be needed in each state or territory affected, 

as well as some personnel for national functions. The 

National Guard leaders making this proposal did not 

present a specific number of personnel for administrative 

functions, other than to suggest that they believed the 

Space National Guard could operate with a relatively 

small amount of overhead. Because the estimate for a 

smaller Space National Guard is structured to reflect the 

National Guard Bureau’s proposal, CBO included a lean 

force that consisted of approximately 100 additional 

full-time personnel to perform national functions and 

an additional 20 full-time personnel for each state and 

territory (for 260 additional personnel in total). If such a 

lean force was not achievable, costs would be higher.7

7. The assumptions used in CBO’s estimate would produce a 

Space National Guard with a much lower proportion of overhead 

positions than the Air National Guard. Using the 260-person 

estimate above for new overhead positions (plus the 50 to 90 

personnel for a training pipeline that also would be transferred 

to the Space National Guard) would yield a ratio of 0.21 to 0.23 

for the Space National Guard. By comparison, the Air National 
June 2020 Costs of Creating a Space National Guard 5

For its estimates of personnel costs, CBO used annual 

costs of approximately $51,000 for a part-time position 

and $268,000 for a full-time position. Those amounts 

are based on average O&S costs per capita for Air 

National Guard personnel, as reported in DoD’s most 

recent budget submission.8

CBO estimates that the new costs of the February 2020 

proposal would result from the following: the (uncertain) 

requirement for additional overheard personnel to 

perform national functions and to augment state organizations in the affected states and territories, and some 

allowance for national functions such as advertising 

for recruiting. Those 260 additional personnel, who 

would be full-time personnel, would result in O&S costs 

of approximately $70 million per year (260 full-time 

personnel at a cost of $268,000 each per year). CBO 

also estimates that $30 million per year would support 

national functions.

According to CBO’s estimates, there would be minimal 

onetime costs to construct additional facilities to support 

the Space National Guard—their current armories and 

other facilities, which would be transferred along with 

the units, would suffice. However, a new national headquarters with 100 additional personnel could require 

about $20 million in military construction. Because the 

February 2020 proposal would not create new units, CBO 

estimates that there would be no significant onetime costs 

to equip those units (because they are already equipped).

For its estimate of construction costs, CBO used a 

per-project cost of slightly less than $20 million. That 

amount is based on the funding requested over the 

past four years in DoD’s budget submissions for the 

Air National Guard for such projects.

An alternative organization, a Space Force Reserve, of 

the same size would probably have essentially the same 

costs—National Guard and reserve units have very 

Guard has a ratio of 0.68 overhead positions for each position in 

operational units. If a Space National Guard required overhead 

positions at a ratio comparable to that of the Air National Guard, 

it would need an additional 1,030 personnel (about one-quarter 

of which would be full time, with the remainder being part time) 

rather than 260. That would increase annual costs by about 

$140 million a year rather than by $100 million.

8. Funding for O&S is the sum of two appropriation titles: 

military personnel and operation and maintenance. O&S 

generally represents recurring costs to maintain forces, unlike 

appropriations for purchasing equipment or constructing new 

facilities, which generally represent onetime costs.

similar costs for their personnel and units. Moving 

existing units from the Air National Guard and Army 

National Guard to a Space Reserve might result in 

slightly lower costs (because they would not need additional personnel within state organizations) or the same 

costs (if the functions performed by those personnel still 

needed to be performed but using national staff instead 

of state-level staff).

Costs of a Larger Space National Guard

CBO also examined the costs of establishing a larger 

Space National Guard, which would be more similar in 

scope to the Air National Guard in two ways. First, the 

relative size of the active and reserve components would 

be similar. Second, the geographic spread of the Guard 

would be wider—both the Air National Guard and the 

Army National Guard are present in every state, the 

District of Columbia, and several territories.9

Description

If a Space National Guard were to reach a size that was 

proportional to the Air National Guard’s size relative to 

the Air Force (about 32 percent of the size of the active 

component), then the Space National Guard would 

probably be considerably larger than the 1,500 personnel presented in the February 2020 proposal. Although 

DoD has not fully defined its vision for the eventual 

size of the Space Force, the Comprehensive Plan for the 

Organizational Structure of the U.S. Space Force suggested 

that the active component would consist of 15,000 to 

16,000 military personnel. In an earlier report, CBO 

estimated that the AC of a new Space Force within the 

Department of the Air Force would consist of about 

18,000 military personnel.10 Assuming a Space Force 

consisting of 15,000 to 18,000 AC military personnel 

and the same National Guard fraction as the Air Force 

9. The only territories without National Guard units are the 

Northern Mariana Islands, American Samoa, and the Minor 

Outlying Islands. In recent years, the Congress has considered, 

but not passed, legislation to establish National Guard units in 

the Northern Mariana Islands.

10. See Congressional Budget Office, The Personnel Requirements 

and Costs of New Military Space Organizations (May 2019), 

www.cbo.gov/publication/55178. CBO’s estimate for a space 

force within the Department of the Air Force presented all 

personnel requirements in full-time-equivalent positions, without 

considering whether those positions would be filled with active or 

reserve military or civilian personnel. However, if the Space Force 

filled those positions with the same ratio of active and reserve 

personnel that the Air Force does currently, the midpoint of that 

estimate would show about 18,000 active component military 

personnel.
6 Costs of Creating a Space National Guard June 2020

(32 percent) would suggest a Space National Guard of 

4,900 to 5,800 personnel.

Such a Space National Guard might still not be large 

enough to allow for National Guards in all of the states 

and territories that currently have Air and Army National 

Guards. There is presumably some threshold below 

which a state Space National Guard would be too small 

to be viable as an organization (a concern that has been 

raised in discussions about creating a Northern Mariana 

Islands or American Samoa National Guard). It is 

unclear to what degree a Space National Guard in states 

and territories with existing National Guards would be 

able to rely on existing personnel in state organizations, 

rather than requiring additional personnel to operate as 

a separate service. Each additional state or territory that 

had a National Guard probably would require at least 

one construction project (an armory or similar facility). 

Costs

If the space-related units in the National Guard today—

which consist of 1,500 personnel—were transferred to 

the Space National Guard, this option would require 

another 3,400 to 4,300 personnel (to reach a total of 

4,900 to 5,800 personnel). Those additional personnel 

would be a mix of full-time and part-time personnel, which reflects the current composition of the Air 

National Guard. (Approximately 25 percent are full-time 

personnel, costing an estimated $268,000 each, and 

about 75 percent are part-time personnel, costing an 

estimated $51,000 each.)11 Those personnel would result 

in additional operation and support costs of $355 million to $460 million per year. CBO also estimates 

that $30 million per year would be needed to support 

national functions, resulting in total O&S costs of 

$385 million to $490 million per year for this option.

In addition, CBO estimates that the larger Space 

National Guard would require $400 million to 

11. Thus, the lower end of that cost range would require about 

850 full-time and 2,500 part-time personnel (for a total of 

roughly 3,400 additional personnel), and the higher end of that 

cost range would require 1,100 full-time and 3,200 part-time 

personnel (for a total of 4,300 additional personnel).

$900 million in onetime costs to construct additional 

facilities (such as armories) and to equip the new units. 

The difference in onetime costs between the low and 

high end of that range primarily reflects the number 

of construction projects a more geographically limited 

Space National Guard might require versus the much 

larger number of construction projects that might 

be needed for a Space National Guard that would be 

present in all states and territories that currently have 

Air and Army National Guards. At the lower end of 

the range, the Space National Guard would be present 

in fewer than half of the states and territories and thus 

would require relatively few construction projects. At the 

high end of the range, the Space National Guard would 

be present in all states and territories and thus would 

require more construction projects.

This Congressional Budget Office report was prepared 

at the request of the Chairman and Ranking Member of 

the Senate Armed Services Committee. In keeping with 

CBO’s mandate to provide objective, impartial analysis, 

the report makes no recommendations.

Adam Talaber prepared the report with guidance from 

David Mosher and Edward G. Keating. David Newman 

and Matt Schmit assisted in the research.

Michelle A. Dolfini-Reed of CNA provided helpful 

comments. (The assistance of external reviewers implies 

no responsibility for the final product, which rests solely 

with CBO.) 

Jeffrey Kling and Robert Sunshine reviewed the report. 

Loretta Lettner was the editor, and Jorge Salazar was 

the graphics editor. An electronic version is available on 

CBO’s website (www.cbo.gov/publication/56374).

CBO continually seeks feedback to make its work 

as useful as possible. Please send any comments to 

communications@cbo.gov.

Phillip L. Swagel

Director