Lesson 2 of 4 · Make a small spacecraft fit its budgets
Make a small spacecraft fit its budgets
6 minute lesson · 3 checks along the way
Your goal for this lessonExplain how subsystem interfaces, energy and test conditions constrain a CubeSat mission.
In this lesson 3 sections · 3 checks
Read & understand
One compact package still contains a system
A CubeSat needs power, communication, computing and a structure even when its payload is small. A camera adds demands for mounting, electrical supply, commands and data storage. The useful design question is how those functions work together within the chosen package, rather than how many components can be squeezed inside it.
NARSSCube’s subsystem-development purpose makes these interfaces central to the story. An electrical connector needs a pin definition and voltage range; a data interface needs message meaning and timing. A successful test of an isolated camera cannot establish that its startup demand or data bursts fit the assembled satellite.
Check 1 of 3
10 pointsUse the reading above. You can try again without losing points.
Read & understand
Energy is power accumulated over time
Consider an entirely fictional CubeSat with 2 watts of baseline demand throughout a 90-minute orbit. That consumes 3 watt-hours because 90 minutes is 1.5 hours. A camera drawing an additional 3 watts for 10 minutes consumes another 0.5 watt-hours. The total load energy is 3.5 watt-hours, before any other losses. These are teaching values, not NARSSCube specifications.
If the fictional solar system supplies a useful 4 watts for 60 minutes and none during 30 minutes of darkness, it delivers 4 watt-hours. The simple orbit total leaves 0.5 watt-hours beyond those loads. That does not prove the battery handles the dark interval or the camera’s peak current: the time distribution, battery limits and conversion losses need separate checks.
An orbit energy total is one part of the design
Original teaching diagram. All values are invented. Bar segments compare energy, not instantaneous power.
Open full-size diagram in a new tab: An orbit energy total is one part of the designCheck 2 of 3
10 pointsUse the reading above. You can try again without losing points.
Read & understand
Test the configuration that matters
A system test should record the hardware revision, software version, wiring and operating conditions. Passing with a laboratory power supply does not establish the behavior of a nearly depleted flight battery. A test that exercises the camera while the radio is idle also leaves their simultaneous demand untested.
For an invented requirement that the camera stay powered during a radio transmission, vary battery condition and run the specified overlap while measuring supply voltage and resets. A failure should lead to diagnosis, a controlled change and a repeat of affected tests. NASA’s verification guidance supplies a general method; it is not a record of undisclosed NARSSCube procedures.
Check 3 of 3
10 pointsUse the reading above. You can try again without losing points.
Put it together
Your lesson progress
Each check connects to a part of the story. Complete all 3 to earn your 25-point lesson bonus.
Explore further · Optional
Go to the source
Explore the evidence behind this lesson. These optional readings and videos open in a new tab.
- Read: BIRDS project newsletter 43: NARSSCube-2 reception, pages 31–32Pages 31–32: participant report of NARSSCube-2 release on 7 August 2019 and first Kyutech reception on 8 August. Historical observations, not present health; some later secondary summaries give a different release date.
- Read: NASA: verifying a system against its requirementsGeneral verification methods used for original teaching examples; not documentation of NARSSCube’s undisclosed test procedures.