National Aeronautics and 

Space Administration

www.nasa.gov

EXAMPLE

How much do just the computers, cameras, and 

structure weigh?

 Multiply the weight of each component by how 

many of them there are:

200 kg × 1 structure = 200 kg

90 kg × 2 computers = 180 kg

20 kg × 3 cameras = 60 kg

 Then add up your results:

200 kg + 180 kg + 60 kg = 440 kg total weight

PROBLEMS

1. What is the total weight of the satellite?

2. Optical transmitters, which use lasers instead of radio 

waves to send more data, weigh less and need less 

power. If the optical transmitter weighs 7 kg, how 

much less does it weigh than the radio transmitter?

The National Aeronautics and Space Administration 

(NASA) reaches for new heights and reveals 

the unknown for the benefit of humankind. 

To accomplish this mission, NASA launches 

satellites that study the universe. NASA's space 

communications and navigation equipment allows 

these satellites to communicate data about our 

planet and the solar system back to Earth.

To launch a satellite into space, you need a rocket. 

Heavier satellites need bigger rockets, so NASA 

tries to make the satellites weigh as little as possible. Help NASA check how much its upcoming 

satellite will weigh by looking at the table below: 

Components Weight Number of 

Components

Structure 200 kg 1

Computers 90 kg 2

Solar Panels 12 kg 4

Batteries 57 kg 2

Cameras 20 kg 3

Radio Transmitter 42 kg 1

REMEMBER: On Earth, 1 kilogram (kg) weighs 2.2 pounds (lb).

NASA Space Communications 

and Navigation

CCSS.MATH.CONTENT.4.MD.A.2

STEP 1

STEP 2

ACTIVITY SHEET

Measurement and Conversion of Measurements GRADES 3–5

PAGE 1

Optical 

transmitters

Satellite

Starfinder

“Optical” means “relating to sight.” Human eyes see light 

in a similar way. Optical communications use telescopes 

both to send flashes of light and to see them from far away. 

This allows NASA to send and receive information—from 

space—with light. 

(continued)
PAGE 2

Measurement and Conversion of Measurements

PROBLEMS (continued)

3. If we remove the radio transmitter and replace it 

with an optical transmitter, what is the new total 

weight of the satellite?

4. Since our new optical transmitter uses less power, we 

can also remove one solar panel and one battery. 

a. What is the new total weight of the satellite?

b. How much weight have we removed since we 

started?

NASA’s Laser 

Communications Relay 

Demonstration (LCRD)

is the next step in 

optical communications.

Hosted on a U.S. Space Force spacecraft, 

LCRD will demonstrate optical technology 

in geosynchronous orbit (which means the 

spacecraft will stay over the same part of Earth) 

22,300 miles above Earth’s surface. LCRD is 

built and managed by NASA’s Goddard Space 

Flight Center in Greenbelt, Maryland.

LCRD is a technology demonstration that will 

pave the way for future optical communications missions. When NASA has developed 

a new way to solve a problem and wants 

to show how it works, they create a technology demonstration. LCRD’s first orbiting 

experimental user will be the International 

Space Station's Integrated LCRD Low-Earth 

Orbit User Modem and Amplifier Terminal 

(ILLUMA-T). The equipment will receive science data from experiments and instruments 

aboard the space station and then transfer 

the data to LCRD, which will then transmit 

them to a ground station. After the data arrive 

on Earth, they will be delivered to operation 

centers and scientists to help make decisions 

about the mission.

LEARN MORE

Learn more about LCRD’s predecessor, 

the Lunar Laser Communications 

Demonstration (LLCD), at 

http://go.nasa.gov/LLCD_history.

Learn more about LCRD at 

http://go.nasa.gov/LCRD_overview.