J-Cube: Frequently Asked Questions
1. General

Question 1
What do 1U and 2U and 3U mean?
Answer 1
These are CubeSat sizes. In the beginning (before the Year 2000), CubeSat sizes were notstandardized. They were designed with many sizes, many shapes, and many configurations.
So this made deployment expensive because the deployers varied.

Then the world decided to converge on a size standard. The CubeSat standard was born. So
roughly:
1U = 10 cm x 10 cm x 10 cm
2U = 10 cm x 10 cm x 20 cm
3U = 10 cm x 10 cm x 30 cm

Question 2So the size is standardized. Is the bus standardized?
Answer 2
Yes and no. Many CubeSat developers design one from scratch, for a variety of reasons. For
example, some developers enjoy this challenge.
You can buy a bus commercially -- but these are costly. On the other hand, you can get started
right away with your payload development. If your budget is limited: We recommend theBIRDS Bus. It has flight heritage from BIRDS-1, BIRDS-2, BIRDS-3, and BIRDS-4 satellite
projects. You can use it on an open source basis (MIT License). This means the designs arefree; but you have to buy components and assemble them. The BIRDS Bus is particularly
suitable for capacity building (universities, high schools, developing countries, etc.).
Go here for information on the BIRDS Bus:
https://birdsopensource.github.io/

Question 3
How does my CubeSat get into space?
Answer 3
There are two methods:(1) Direct rocket launch1(2) ISS (International Space Station) deployment
For (1), your satellite rides into space on a rocket.
For (2), your satellite first gets delivered to the ISS. Then, from there, it gets deployed into
low-earth orbit. Advantage: Your satellite need not be as robust as for (1). (1) is a more violent
ride. Disadvantage of (2): Your orbit does not deviate from the ISS orbit very much (between
450 and 480 km above the Earth). And the orbit inclination is similar to the ISS inclination.
Advantage of (1): If you need a much higher orbit (say 800 km), then it is possible. Just findthe rocket that would take it there. However, note that (1) is usually more expensive than (2).

Question 4
What is the difference between KiboCube and J-Cube?
Answer 4
KiboCube is a program between UNOOSA and JAXA; it was started in 2015 (it is about 7years old). The launch is free, but getting KiboCube is hard: several parties (nations) competefor it. And often, KiboCube is offered to only one party per year. So it is hard to get. But it
is free, if you get it.
J-Cube is a program between JAXA and UNISEC; it was started in 2021 (it is less than oneyear old); it just got started. It is not free like KiboCube; rather, it is low cost. Main advantage:If you put up that money, then you have a slot to go to the ISS. But only 12U is offered peryear; so slots go to applicants on a "first come, first serve" basis. Nevertheless, your odds ofsuccess are much higher than with KiboCube. You should consider J-Cube for a secure, lowcost ride into space.
By the way, both are ISS deployments under JAXA supervision.

Question 5
I have no time and no skills to make a satellite. Can I just buy a 1U CubeSat?
Answer 5
Yes, there are many vendors, such as GOMSPACE. In some cases, this would be the best
option for you. However, if you want to train engineers on space engineering, then that option
is no good. As a first step, buy components from GOMSPACE (for example) and challenge
your engineers to put it together. This approach has been tried by many first-time projects (e.g.,
the Irazu Project of Costa Rica).
When you buy CubeSat components, it is recommended to buy from a single vendor ascomponents from different vendors often have problems of interface incompatibility.

Question 6
My country is launching a satellite for the first time. How do I raise the funds for it?

2Answer 6
This money problem has been faced by many institutions in many nations. Here is some advice.
For the first satellite, it is hard to get government funding because you lack credibility. On theother hand, it is easy to collect donations because, after all, it is the First Satellite of YourNation. For many patriots, being first is significant. If you are creative and energetic, you canraise the needed funds. Others have done it.
For the second satellite, the situation reverses. It becomes hard to get donations: Few people
care about donating money for the second satellite. They usually only care about No. 1. On
the other hand, if your first satellite was reasonably successful, then you have credibility. You
can approach the government for funding; we are sure they will listen to your case.

Question 7
What is the time slot for J-CUBE application?
Answer 7
May to December in every fiscal year. However, match-making deadline is much earlier.

Question 8
Is J-CUBE intended for only emerging countries or it could be also for developed nations
such as UK universities?
Answer 8
At present only emerging/ developing countries are considered since one of the main
objectives is capacity building.

Question 9
How much financial value or capital should applicant nations have?
Answer 9
Applicant nations need a solid financial base, hence a secured budget is very important.

Question 10
How do prospective nations proceed to find Japan partners with the matching system?
Answer 10
Contact UNISEC (J-CUBE office: info-jcube(at)unisec.jp) for further information. [Replace(at) with @]Question 11
What should be the state of satellite development before applying for the J-CUBEframework?
3Answer 11
The satellite could be at the early documentation stage. It should have mission definitions,secured budget and workable timelines.

Question 12
What is the general timeline?
Answer 12
The timeline would depend on the partnering institutions and the nature of the project.
Generally, 6 months is the minimum period required for safety review processes. Assuming
the satellite is already built, then 6 months could be the minimum period for the intended
project. Typically, 1-2 years is required for a satellite project.

Question 13
Are safety review requirements provided by JAXA before building satellites?
Answer 13
No. Prospective applicants must use the JEM payload accommodation handbook as a guide.
Safety review process starts after initiating launch contract procedures.

Question 14
Do only payloads for missions’ demonstrations qualify for partnerships with Japan
universities under the J-CUBE framework?
Answer 14
Yes.

Question 15
What should be the size of the CubeSat under J-CUBE framework?
Answer 15
It could be a 1, 2, or 3 U satellite.

Question 16
Can the partnerships be only for launch opportunities?
Answer 16
If the applicant nation can show a mutual benefit to be gained by the Japan university partner,
then maybe Yes.

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Question 17
Does satellite development need to be started before finding partner of Japan Universities?
Answer 17
No. Satellite can be just on paper.
Question 18
Are the fees to be paid only for launch under the framework?
Answer 18
No. Other service charges must be considered like environmental testing fees, safety review
processes fees, et cetera.

Question 19
What would be the minimum size for a CubeSat with multi-spectra imaging system?
Answer 19
The payload alone could take about 3 U volume. Considering the bus and other subsystems, 6
U size should be fine.

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2. Training matters

Question 1
What is the required English proficiency level for space science & engineering graduate
programs in Japan?
Answer 1
For an example, in Kyushu Institute of Technology, candidates are required to submit anofficial test score of a standardised test (such as TOEFL) equivalent to the Common European
Framework of Reference for Languages (CEFR). The grade for CEFR must be B2 or higher.
The requirement levels differ depending on universities you apply to.

Question 2
Is Japanese language necessary for admission into JP universities?
Answer 2
It is not a requirement. However, English proficiency might be required by some universities.

Question 3
How much time is required to apply for graduate programs?
Answer 3
A minimum of 6 months. For instance, April admissions are opened in October of the previous
year and closes approximately 2~4 weeks later. The exact application period depends on theschool you apply to.

Question 4
What is the minimum requirement for a graduate degree program applicant in Japan?
Answer 4
When applying for master’s program in typical Japanese universities, you are required to showthat you have attained a minimum of 16 years of schooling up to the bachelor’s degree level.
You should submit transcripts and official degree certificates as a proof.
When applying for a doctoral program, you should submit official master’s degree certificate(& completion certificate if available), in addition to official academic transcripts.
If you expect to finish the Bachelor or master’s degree by the time of your enrolment in Japan,
you need to prepare an official letter from the school to say that you are expected to graduate
with a degree.

Question 56

Is there financial support for graduate students?
Answer 5
Financial support comes as scholarships/ grants which are quite competitive. It is better tosecure funding or some sort of scholarship for your graduate study. In Japan there are various
types of scholarship from both government and private organisations.

Question 6
In developing our satellites, could we have assistance from Japanese universities?
Answer 6Yes. Having a collaborative research agreement (CRA), i.e., a contract, is a good approach. For
instance, in Kyushu Institute of Technology, the CRA includes environmental testing of yoursatellite to meet JAXA’s standard, assistance with safety documents preparations, as well asdelivering the satellite to JAXA to be launched to the ISS and released from there.

73. Safety Review/ Deployment matters

Question 1
What are the requirements that our CubeSat needs to meet (dimensions, weight, electricaldesign, etc.)?
Answer 1
Read the Japanese Experiment Module (JEM) Payload Accommodation Handbook. Do notdeviate from it. Otherwise, you will be in trouble.

Question 2
Regarding early operation of the satellite, what are the requirements or restrictions for thebeacon? Can the satellite emit a beacon automatically immediately after the deployment fromISS? Or do we have to send a command to start the beacon transmission?
Answer 2
The satellite should not transmit any radio signals until it is sufficiently far from the ISS (morethan 30 minutes after the satellite is released).
If the satellite emits a beacon automatically, (most university CubeSats have this option,because there is less chance of losing the satellite signal), you can ask other ground stations toreceive the beacon signal. Many satellites using amateur radio frequencies ask the amateur
radio community to receive the beacon signal.

Question 3
Can RBFs or fuses be used as inhibit functions in EPS circuits?
Answer 3
Remove Before Flight (RBF) pins cannot be used as an inhibit function because the satellite
deployer has no access window.
A fuse may be used as a short circuit prevention function, but functional evaluation is required.
CubeSat uses batteries and solar cells as its energy sources. The satellite needs to have 3 inhibits
to prevent the power at battery or solar cell from reaching the payload. In addition, the safetyfunctions are required for battery overcharge protection, over-discharge protection, and shortcircuit protection. When mechanical switches or electronic switches (MOSFETs) are used forthe inhibits, these are regarded as safety functions.

Question 4
Can we have triangular shape at the rail end?
Answer 4No. Multiple CubeSats will be installed in the satellite deployer. Other satellites may be
mounted on the +Z side of your satellite. At that time, the +Z end face of the rail is in contact8

with the -Z rail end face of the satellite in front. Normally, a deployment switch or spring
plunger is attached to the end face of the -Z rail of CubeSat. If the +Z rail end face does nothave enough face, this deployment switch or spring plunger cannot be pushed in. Therefore,
you need to use rails that meet the requirements of the JEM Payload Accommodation
Handbook.

Question 5
Companies such as ISIS and Exolaunch are providing deployer systems that utilises the internal
volume of POD more efficiently. At the end of the deployer, there is an open volume to accept
a Tuna can type antenna system or others. Can we use a Tuna can type antenna system?
Answer 5
No. The backplane of the satellite deployer used by J-Cube is a flat plate. There is no hole/
opening for the Tuna can to go through. Therefore, you cannot use the Tuna can type antenna.

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