unisat

CubeSat 1.5U — Operations Guide

Profile key: cubesat_1_5u · Mass cap: 2.0 kg · Volume: 1702 cm³ Template: mission_templates/cubesat_1_5u.json · BOM: hardware/bom/by_form_factor/cubesat_1_5u.csv

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1. Mission class

Non-standard intermediate form factor between 1U and 2U. Useful when a payload needs ~30 % more volume than a 1U can offer but the launch provider’s slot billing is per-U. Same mechanical footprint as 1U, 170 mm tall instead of 113.5 mm.

Typical users: imaging teams where the camera + baffle chain is exactly 130 mm; tech-demo missions that need a deployable antenna longer than a 1U can hide.

2. Physical envelope

Parameter	Value
Mass cap	2.0 kg
Dimensions	100 × 100 × 170.2 mm
Volume	1702 cm³
Power generation	~3.5 W orbit-average
Nominal consumption	2.8 W
Battery	3× 18650 Li-ion, ~30 Wh

3. Regulatory context

Same as 1U — CDS rev 14, ITU coordination, launch-provider ICD. Most launch-provider slots are 1U × N, so a 1.5U must be billed as two 1U slots unless the provider supports 0.5U increments (a few do, notably ISIS and D-Orbit).

4. Subsystem matrix

Subsystem	1U	1.5U
S-band	❌	❌
Reaction wheels	❌	❌
Magnetorquer ADCS	✅	✅
GNSS	✅	✅
Camera (8 MP)	⚠	✅
Deployable antenna	⚠	✅
Dual OBC redundancy	❌	⚠ (tight)

5. Build

make target-cubesat-1_5u

Compile-time macro: MISSION_PROFILE_CUBESAT_1_5U=1.

6. Mission config

cp mission_templates/cubesat_1_5u.json mission_config.json

Same adjustment list as 1U plus:

• Verify launch provider bills in 0.5U increments; otherwise stick with 2U.
• If using a deployable antenna, add the mass estimate to satellite.mass_kg.

7. Mass & volume validation

Metric	Value	Status
Total mass	1.68 kg	≤ 2.0 kg ✅ (16 % margin)
Volume used	500 cm³	29 % of 1702 cm³ ✅

A 1.5U has a comfortable margin for a moderate camera + deployable antenna. Still no room for reaction wheels — the AdcsTier gate stays at magnetorquer.

8. Typical mission phases

Same as 1U (cubesat_leo profile).

9. Testing checklist (ground qualification)

Legend: [x] = verified in software / CI / SITL (passes in the current release); [ ] = requires bench hardware, RF range test, or flight-day field activity — team must sign off manually.

Same as 1U plus:

• Verify deployable antenna fully extends in thermal-vacuum at -20 °C.
• Check centre-of-mass offset from geometric centre < 2 mm (CDS §3.1 requirement).
• Confirm moment of inertia along each principal axis within ICD tolerance.

10. Flight-day checklist

Same as 1U.

11. Known limitations

Same as 1U. The extra 55 mm of height mostly buys you volume, not power — body-mounted panels on a 1.5U add only two extra cells compared to 1U, so the orbit-average generation gain is ~30 %.

12. Post-flight debrief

Same as 1U.

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