STELLAR / Engineering Visualizations Lab / Node-1

Explore the Node-1 architecture

Interactive diagrams and 3D views of STELLAR's first orbital data-center payload: orbit model, payload interfaces, compute path, thermal loop, storage architecture, and verification flow.

Review question

Can Node-1 operate as a hosted orbital data center payload within the closed 500 km SSO, 95 kg allocation, 838 W peak waste heat, storage-integrity, and ground-contact constraints?

500 km SSO

Orbit

95 kg

Payload

43% margin

Thermal

42-55 min/day

Contact

Node-1 ADR-002 closed baseline

Interactive orbital twin

stage playback / drag to inspect

Mission · STELLAR Node-1NOMINAL OPS

Orbital state

ALT500.0 kmINC 97.4°METT+ 0.0 minSUNINSOLATED

Orbital elements

a6878 kme0.0001i 97.4°P94.6 minMET00:00:00ν 0.0°β+32.0°GT 7.61 km/sR 100 kmΔv+ 0.00 km/sECL35% · 33 minAOST-12:34

SSP 0.00°N 0.00°E

Mission telemetry

DLINK480 Mbps · DLKCPU78% · 20.3 TSTOR1.10 / 2.00 TBPWR 940 W·SOLHEAT 780 W heat

Active CONOPS phase

Nominal Orbit Ops

Per 96 min orbit

Receive, validate, stage, infer, checkpoint, store, prioritize, and downlink high-value products within pass windows.

Compute activeabout 60%

Peak runup to 40 min

Ground passes4-8/day

STELLAR engineering architecture and infrastructure overview

STELLAR / engineering architecture overview

00 / review sequence

Structure before visualization

The page now follows the order a serious technical review would expect: define the question, lock assumptions, show the system architecture, define interfaces, prove operations, then trace claims to evidence.

Step	Review area	Purpose
01	Mission baseline	Close orbit, contact, radiation, and link-budget assumptions before architecture claims.
02	System architecture	Show ground, bus, payload, data, thermal, and verification ownership in one end-to-end view.
03	Payload ICD	Define the hard boundary between host bus services and payload-owned compute/data/thermal functions.
04	CONOPS	Prove the system can operate through launch, commissioning, nominal cycles, degraded ops, and safe mode.
05	Closure evidence	Tie thermal, storage, reliability, and provenance diagrams to testable verification products.
06	Open actions	Separate closed decisions from draft analyses so the page does not overstate technical maturity.

01 / baseline register

Closed assumptions and open analysis items

A professional visual system must show what is closed, what is draft, and what still needs evidence. The X-band budget is intentionally marked draft because the current budget range does not yet match the closed orbit ADR.

Parameter	Value	State	Authority
Orbit	500 km SSO	Closed	ADR-002
Inclination	97.4 deg	Closed	ADR-002
Local time	10:30 LTAN	Closed	ADR-002
Payload allocation	95 kg hosted	Closed	ADR-001
Thermal load	838 W peak / 1,200 W rejection	Closed sizing	ADR-003
Compute path	XQRVC1902 FPGA / 26 TOPS + GR740 mgmt	Closed architecture	ADR-004
Storage path	ECC DDR4 + 2 TB RAID-1 + 128 GB queue	Closed architecture	ADR-005
X-band throughput	100-500 Mbps class	Draft	T07 reconvergence

02 / end-to-end architecture

Source-to-result system architecture

This board replaces the “collection of diagrams” feeling with a single system map: ground segment, space segment, hosted bus responsibilities, payload functions, data flow, thermal flow, and evidence loop.

STELLAR / SYSTEM ARCHITECTURE / REVIEW CONTEXT

Node-1 orbital data center · source-to-result architecture

Customer workload, ground segment, host bus, payload compute, thermal control, storage integrity, and verification evidence tracked in one view.

AGround segment

Customer data
tasking files / model input / policy
Mission operations
command validation / schedule / health
Ground station
X-band receive / S-band TT&C
Delivery system
receipt · audit replay · customer handoff

BSpace segment

Host bus

EPS / ADCS / TT&C

Launch / propulsion

Payload

95 kg allocation

Compute · storage · RF

Orbital frame

Node-1500 km SSO · 97.4° · 42–55 min/day contact

CPayload functional chain

Step 01

Authenticate + stage

Validate source, schema, policy, workload bounds.

Step 02

Execute inference

XQRVC1902 primary, GR740 supervision, checkpointing.

Step 03

Persist + rank

ECC cache, RAID-1 mission store, priority queue.

Step 04

Downlink + prove

X-band transfer, receipt, SHA-256 provenance.

Sequence

01020304

Thermal pathcold plates → LHP → 5.0 m² deployable radiators

Customer data → groundGround → space contact (X-band / S-band)Payload result → deliveryThermal path

Verification framework — REQ to V&V

REQ01 / 5

Requirements

mass · power · orbit · contact · thermal · data assurance

ANL02 / 5

Analysis

STK · GMAT · RF budget · thermal model · radiation model

ICD03 / 5

Interfaces

bus services · payload envelope · comms · thermal · datums

OPS04 / 5

Operations

commissioning · nominal · degraded · safe-mode

V&V05 / 5

Evidence

test reports · sim artifacts · pass logs · receipts

03 / mission geometry

Orbit, access, and X-band assumptions

The orbit board is deliberately split between closed ADR facts and draft RF performance. That is the kind of separation a serious reviewer will look for immediately.

STELLAR / MISSION GEOMETRY · BOARD 01

Node-1 · 500 km SSO access model

Closed orbit baseline with the draft X-band throughput envelope visibly separated from the closed ADR facts.

Orbit · 500 km SSO @ 97.4°10:30 LTAN

Active node

500 km · 97.4°

Primary pass4–8 passes/day · 42–55 min/day aggregateSecondary

X-band ACM envelopeDraft · pre-reconciliation

Y · commanded rate (Mbps)X · elevation (°)

Measured (solid) tracks the closed 500 km SSO baseline. Draft (dashed gold) is the original 600 km budget kept on-screen for reconciliation.

500 km SSO

Closed orbit

97.4 deg

Inclination

10:30 LTAN

Local time

~35 min/orbit

Eclipse

42-55 min/day

Daily contact

7-10 years

Natural decay

Plot legend

Measured throughput · 500 km SSO

Draft budget · 600 km, pre-reconciliation

Primary X-band pass · per-orbit

Secondary opportunistic pass

Reconciliation required

Link table is draft; orbit ADR is closed.

Visualization stays anchored on the 500 km SSO baseline. Throughput is shown as class-level until the X-band RF budget is reconverged from the draft 600 km range.

X-band ACM envelope · sample points

Elevation	Slant range	Commanded rate	Note
5°	2,300 km	105 Mbps	low elevation acquisition
10°	1,530 km	260 Mbps	minimum robust operations
20°	960 km	440 Mbps	high-throughput region
30°	720 km	500 Mbps	modulator limited
60°	620 km	500 Mbps	zenith shoulder
90°	600 km	500 Mbps	draft budget zenith

04 / payload ICD

Hosted payload boundaries and ownership

The payload drawing is not trying to be manufacturing CAD. It is an interface-control visualization: bus services, payload allocation, connector ownership, compute/storage routing, RF path, and heat rejection.

STELLAR / NODE-1-FM-PAYLOAD · BOARD 02 · HOSTED PAYLOAD ICD

Payload cutaway · adapter frame · interface boundaries

Commercial host bus boundary, 95 kg payload envelope, compute / storage stack, RF path, cold plate, LHP, and deployable radiators in one traceable view.

Section A-A · +Z panel removed for internal payload viewDatum A · B · C

ICD connectors · datum A

J1
Power
28 V EPS switched payload bus
J2
Data
Mission data bus · SpaceWire–Eth bridge
J3
Safe-mode
Safe-mode discrete + watchdog
J4
RF · TT&C
S-band TT&C telemetry handoff
T1
Thermal
Thermal clamp · LHP condenser return
M1
Mechanical
4× shear-tie mechanical datum set

Host bus envelopeEPS · ADCS · prop · launch · TT&C

STELLAR payload envelope · 95 kg hostedDatum B · adapter frame

PDUPayload PDUInput filter · switched loads28 V → bus rails

FPGAXQRVC1902Rad-tol FPGA · ~26 TOPSInference fabric

CPUGR740 mgmtLEON4 ×4 · 250 MHzMode + watchdog

MEMStorage16 GB ECC · 2 TB RAID-1+128 GB priority Q

RFX-band chainDVB-S2X ACM100–500 Mbps class

Cold plate + LHP manifold→ 838 W rejection · 1,200 W radiator capacity · 43 % margin

Datum C · radiator hinge lineSection A-A reference

Radiator wing A · deployed

Radiator wing B · deployed

Interface boundary registerBoundary ownership

POWERbus → payload
28 V regulated input · switched load enables
Payload sheds nonessential loads first
DATApayload → bus
Mission data + health telemetry packets
Checkpoint before reset / pass gap
THERMALpayload → radiator
Cold plate · loop heat pipe · deployable area
Throttle before 838 W case exceeds margin
MECHbus ↔ payload
95 kg hosted envelope · datum set A / B / C
Loads close through host adapter frame
RFpayload → ground
X-band mission downlink · S-band TT&C handoff
Queue survives lost contact windows

Closure facts · Node-1 ADRs

Payload allocation

95 kg hosted

Compute primary

XQRVC1902 · 26 TOPS

Management

GR740 LEON4 ×4

Storage

16 GB ECC + 2 TB RAID-1 + 128 GB Q

Thermal

838 W / 1,200 W · 43 % margin

S-band TT&C + X-band mission data

Drawing intent: communication layer · not CAD master

REV. A · visualization ICD · not for manufacturing release

System area	Scope	Owner
Host bus	EPS, ADCS, propulsion, launch integration, primary TT&C	Partner spacecraft provider
Payload compute	FPGA inference fabric, management CPU, workload isolation, checkpoints	STELLAR payload team
Mission data	ingest validation, storage, priority queue, downlink receipts, provenance chain	STELLAR data systems
Thermal	cold plates, LHP routing, deployable radiators, throttle rules	Payload thermal + host bus interface
Ground segment	command authorization, pass scheduling, X-band receive, delivery reconciliation	Mission operations

Subsystem	Technical definition	Design note
Partner Bus	Power, ADCS, propulsion, launch integration, primary TT&C	Hosted-payload first; free-flyer transition planned for Node-3+
Compute Module	XQRVC1902 rad-tolerant FPGA, 26 TOPS inference; GR740 management processor	Jetson Orin retained as qualified fallback path
Storage Stack	8 GB ECC DDR4 hot cache, 2 TB usable NVMe RAID-1, 128 GB result queue, append-only audit log	ECC scrubbing, integrity checks, and SHA-256 hash-chain provenance
Thermal Path	Cold plates, loop heat pipes, and 5.0 m2 deployable radiator panels	838 W peak heat load; 1,200 W rejection capacity; 43% margin
Mission Data Link	S-band command/telemetry plus X-band mission downlink with adaptive coding and modulation	Draft budget targets 100-500 Mbps class X-band by elevation and ground dish

05 / mission operations

Recoverable per-orbit CONOPS

The mission is useful only if results survive pass gaps, resets, SEUs, and storage pressure. This sequence makes each handoff auditable through an artifact, not just a flow label.

06 / thermal and data closure

Thermal, storage, and provenance constraints

Compute throughput is constrained by heat rejection and contact timing. Data usefulness is constrained by integrity, queueing, and replayable delivery evidence.

STELLAR / TECHNOLOGY / BOARD 04 · THERMAL DUTY CYCLE

96-minute orbit · heat rejection closure

40-minute peak compute run, 20-minute cooldown reserve, eclipse derate, and X-band contact passes — all balanced inside a 1,200 W radiator envelope.

Run · Node-1 / nominal SSO30% margin

APower-vs-time · waste heat over one orbit

X · 0–96 min · Y · 0–1.3 kW

Waste heat curveRadiator capacityPeak waste lineEclipse window

BClosure snapshot

Peak waste heat838 W
Radiator capacity1,200 W
Rejection margin43%
Radiator area5.0 m2
Peak compute run40 min
Cooldown reserve20 min

Heat rejection margin

838 W peak1,200 W cap

30% rejection margin

COperating modes · timing and rationale

4 modes · one orbit

Mode M10 → 40 min

Peak compute run

838 W waste heat

Inference workload running at full payload power · LHP at duty.

Mode M240 → 60 min

Cooldown reserve

610 → 430 W

Compute throttled · stored heat dumped through radiator before next pass.

Mode M362 → 96 min

Eclipse derate

about 35% derate

Solar input zero · battery run · payload duty cycled to match thermal budget.

Mode M49–20 min · 51–64 min

X-band contact

overlay events

Two contact passes per orbit · downlink scheduled inside thermal envelope.

Thermal path · cold plate → loop heat pipe → radiator

Stage 01transport

Cold plate

absorbs payload heat at source

Stage 02transport

Loop heat pipe

transports heat without pumps

Stage 03sink

Deployable radiator

5.0 m² area · 1,200 W rejection

Board 05 / Data Reliability

Radiation-aware storage and provenance chain

Tier	Capacity	Protection	Fault	Recovery action
T1 DDR4 hot cache	8 GB per compute node	ECC + 15 minute scrub	SEU bit flip	correct, scrub, checkpoint
T2 NVMe mission store	2 TB usable RAID-1	mirrored writes + integrity verification	device or block fault	mirror read, rebuild, quarantine
T3 Result priority queue	128 GB partition	contact-aware ranking and resumable transfer	pass gap or storage pressure	rank, expire, downlink first
T4 Append-only audit log	SHA-256 hash chain	tamper-evident provenance	delivery dispute	replay manifest and receipt chain

Radiation model note: the storage ADR assumes DDR4 ECC, a 15 minute scrub interval, and checkpoint/restart for inference state recovery.

07 / verification

Trace every claim to an evidence product

This matrix is the professional backbone: each headline technical claim is tied to a source authority, verification artifact, and maturity state.

Verification Matrix

Requirements-to-evidence traceability

This is the piece the prior version was missing: every visual claim must trace to an ADR, engineering model, test artifact, or explicitly open action. The page is allowed to be impressive only after the assumptions are auditable.

ID	Requirement / claim	Authority	Evidence product	State
MDR-01	Mission geometry closes against 500 km SSO, 97.4 deg inclination, 10:30 LTAN.	ADR-002	STK / GMAT access and eclipse report	Closed baseline
MDR-02	Hosted payload remains inside 95 kg allocation and isolates bus-owned services from payload-owned functions.	ADR-001	Payload ICD, mass properties register, adapter load path review	Closed architecture
MDR-03	Compute stack supports radiation-tolerant inference path with management processor recovery supervision.	ADR-004	FPGA benchmark plan, GR740 watchdog sequence, checkpoint/restart test	Verification required
MDR-04	Peak waste heat can be rejected with radiator margin through the orbital duty cycle.	ADR-003	Thermal Desktop / SINDA hot case, eclipse case, degraded-mode throttle case	Closed sizing
MDR-05	Mission products survive SEU, reset, pass gap, and storage pressure without provenance loss.	ADR-005	ECC scrub test, RAID-1 fault injection, hash-chain replay	Verification required
MDR-06	X-band downlink class is traceable to a reconverged link budget at the closed orbit altitude.	T07 draft	RF link budget update from 600 km draft to 500 km ADR baseline	Open action

08 / toolchain

Authoritative tools behind the browser surface

The browser page is a communication layer. The engineering truth should come from flight dynamics, thermal, RF, mission-geometry, and multidisciplinary analysis tools.

Board 06 / Engineering Toolchain

Authoritative tools feeding the visual layer

Domain	Tool family	Engineering role	Artifact consumed
Mission access	Ansys STK / ODTK	Coverage, access, comm geometry, conjunction screening, and operations playback.	access report / CZML
Flight dynamics	NASA GMAT	Orbit analysis, maneuver planning, Monte Carlo cases, and operations support.	ephemeris / maneuver file
Reference geometry	NASA SPICE / NAIF	Frames, time systems, pointing, observation geometry, and mission kernels.	SPK / CK / FK kernels
Flight software math	Orekit	Propagators, frames, attitude, events, and ground/onboard astrodynamics services.	propagation service
Web digital twin	CesiumJS	High-precision WGS84 globe, ephemeris playback, 3D Tiles, and review publication.	interactive 3D ops layer
RF and comms	MATLAB SatCom Toolbox	Time-varying access, link budgets, RF/optical analysis, propagation, and waveform tests.	link budget and ACM table
Thermal closure	Thermal Desktop / SINDA	CAD-based spacecraft thermal models, radiators, heat pipes, orbital cases, and correlation.	thermal case matrix
Sizing trades	OpenMDAO	Mass, power, thermal, contact time, cost, and reliability multidisciplinary trades.	trade study run set

09 / action register

Open technical actions that must not be hidden

World-class does not mean pretending everything is solved. It means making unresolved engineering work visible, bounded, and owned.

Action	Required work	Evidence owner	State
RF-01	Reconverge X-band link budget from 600 km draft range to closed 500 km SSO baseline.	T07 link budget	Open
TVAC-01	Correlate 838 W peak compute thermal case against deployable radiator hot/cold cases.	Thermal Desktop / SINDA	Planned
FSW-01	Run checkpoint/restart fault injection against FPGA reset, GR740 watchdog, and storage pressure cases.	SIL / interface emulation	Planned
OPS-01	Generate commissioning sequence with explicit L+24 h payload power-on and L+48 h initial downlink gates.	CONOPS	Planned

Link-budget note: the current draft X-band budget uses a 600 km nominal range, while the closed orbit ADR sets 500 km SSO. This page uses the closed orbit baseline and labels throughput as class-level until the RF budget is reconverged.