SYS.ID // NADIRLAB.SPACE — ORBITAL VECTOR: -Z · REV 0.1

Earth looks up to the zenith. Orbit looks down to the nadir.

Independent research laboratory operating at the intersection of orbital mechanics, extreme-environment metallurgy, and miniature spacecraft architecture (PocketQube 1p & CubeSat 1U).

LEXICON // SPEC-DEFVECTOR: -Z · REV 0.1

na·dir /ˈneɪdɪər/ — noun [Astrodynamics / Orbital Mechanics]

  1. 1. The local vertical vector (-Z axis) pointing directly from an orbiting spacecraft toward the center of the celestial body below; the directional antithesis of the zenith.
  2. 2. The deepest point; foundational depth.

Scale band

100 mm
3UCubeSat
Envelope
100 × 100 × 340.5 mm
Volume
3,405 cm³
Max. mass
6.00 kg
Standard
CubeSat Design Specification Rev. 14.1 (2022)
Compare 3U with 1P
MANIFESTO // THE ORBITAL PERSPECTIVEVECTOR: -Z · REV 0.1

THE ORBITAL PERSPECTIVE

Everyone on Earth looks up. From the ground, space is an aspiration—a distant zenith. But once a spacecraft achieves orbit, the geometry inverts. To observe, to communicate, and to endure, a satellite must orient itself downward, locking onto the nadir.

nadir lab. adopts this inverted perspective. We are an independent research initiative and publication platform operating at the intersection of miniature spacecraft architecture (PocketQube 1p & CubeSat 1U), extreme-environment metallurgy, and orbital mechanics.

In non-technical language, nadir also denotes the deepest point. For us, depth is a methodology. Instead of viewing aerospace from the surface, we go down to the fundamentals: where structural alloys, thermal coatings, and crystalline lattices confront atomic oxygen, thermal cycling, and the hard vacuum of Low Earth Orbit. We document the physics, the materials, and the engineering of small things built for the infinite dark.

Latest News & Launch Digest

Recent rideshare deployments, orbital telemetry bulletins, and 5-year deorbit regulatory updates.

All news dispatches
Launch Dispatch

Transporter-15 (Alba Flight 10) Deploys HUNITY, SARI-1/2 and ANISCSAT, Pushing PocketQube Census Past 90 Spacecraft

SpaceX’s Falcon 9 Transporter-15 rideshare mission successfully placed four new PocketQubes into Sun-synchronous orbit via SEOPS and AlbaPod deployers, including BME Budapest’s 3P HUNITY and Azerbaijan’s first student PocketQube ANISCSAT.

Read more
Launch Dispatch

Transporter-13 (Alba Flight 9) Deploys Five PocketQubes Including HADES-ICM (SO-125) and Three 3P Unicorn-2 Imagers

Five PocketQubes—Alba Orbital’s Unicorn-2O, 2P and 2Q (3P), AMSAT-EA’s HADES-ICM (1.5P) and Hydra Space’s Hydra-W (1.5P)—were deployed directly via AlbaPod on SpaceX Transporter-13.

Read more
Mission Telemetry

Seven PocketQubes Launch on Transporter-12: First PocketQube-to-ChipSat Optical Link (POQUITO) and Turkish Skylink-1/2 IoT Pair

Alba Flight 8 on SpaceX Transporter-12 deployed seven PocketQubes from six countries via D-Orbit ION, including Luxembourg’s POQUITO, Poland’s HYPE, Portugal’s PROMETHEUS-1, Türkiye’s Skylink-1/2, and Spain’s HADES-R & Hydra-T.

Read more
Policy & Spectrum

Solar Cycle 25 Peak & The 5-Year Deorbit Rule: Why 500–550 km SSO PocketQubes Pass Without Propulsion

Because a 1P PocketQube has twice the area-to-mass ratio of a 1U CubeSat, natural atmospheric drag clears 1P missions from 550 km within 2.5–4.2 years under moderate-to-high solar activity.

Read more

Research

Three research monographs by Çağla Aytaç Dursun, written in academic journal format with AI-assisted workflows and published exclusively in full on nadir lab.: the PocketQube class (standards, 2013–2025 census and flight heritage), the materials engineering of PocketQubes, and non-pyrotechnic NiTi antenna deployment.

All research
Original MonographPublished in nadir lab. Research Monographs20 Oct 2026

PocketQube picosatellites: A review of standards, mission trends and miniaturization constraints, with lessons learned from Grizu-263A, Türkiye’s first PocketQube

Çağla Aytaç Dursun

  • Census of the 77 PocketQubes launched in 2013–2023, including routes to orbit
  • Launch-segment anomalies lost or degraded 17% of all PocketQubes launched
  • A fully loaded 1P has ∼1/4 the power and ∼1/2 the orbital life of a 1U CubeSat
figures
8
tables
9
references
76

Latest articles

Every article states its assumptions; the values in its tables come from the site’s open models and are recomputed at build time.

All articles
DOC // NL-001(SQ-TN-2026-008)VECTOR -ZREV 0.1

G/T from first principles: what makes a good amateur ground station

For a weak downlink such as that of a PocketQube, the ground station contributes a single number to the link budget: its figure of merit G/T. We build the system noise temperature of five amateur receive chains with the Friis cascade. A 13 dBi crossed Yagi with a low-noise amplifier at the mast reaches about 200 K and −10.0 dB/K; moving the same amplifier indoors behind 1.8 dB of cable raises the noise to 366 K, and leaving it out to about 1600 K. Applied to Grizu-263A’s 20 dBm, 4800 Bd downlink, the three chains decode above 5°, 13° and 42° elevation, which at 41.45° N means about 32, 16 and 2 minutes of usable contact a day. Omnidirectional antennas never close at 4800 Bd. We end with a checklist for building and measuring a station.

  • Ground station
  • Noise
  • G/T
  • LNA
  • UHF
  • Grizu-263A
Engineering7 min read
DOC // NL-002(SQ-TN-2026-016)VECTOR -ZREV 0.1

Tracking a 5 cm satellite

A bare 50 mm cube sits deep in the Rayleigh scattering regime for UHF space-surveillance radars, yielding a radar cross-section near −43 dBsm. Once its 437 MHz tape-spring monopole or dipole deploys, resonant wire scattering boosts RCS by 25–30 dB. We examine radar cross-section across UHF, S-band and X-band and explain how Differential Doppler resolves rideshare TLE lotteries.

  • Radar cross-section
  • TLE
  • Space surveillance
  • Rideshare
  • UHF antenna
  • PocketQube
Basic2 min read
DOC // NL-003(SQ-TN-2026-014)VECTOR -ZREV 0.1

Atomic oxygen and polymers in low Earth orbit

Polymers on the exterior of a PocketQube—solar-panel substrates, Kapton insulation, PEEK spools, UHMWPE burn lines and exposed FR-4 edges—face both high-vacuum volatile condensation and 4.5 eV ram atomic oxygen (AO). We review ECSS-Q-ST-70-02C / ASTM E595 screening limits and compute annual AO fluence and recession depth from 350 to 600 km.

  • Atomic oxygen
  • Outgassing
  • Polymers
  • Kapton
  • Materials
  • PocketQube
Academic2 min read
DOC // NL-004(SQ-TN-2026-015)VECTOR -ZREV 0.1

First natural frequency of the backplate and launch loads

Unlike a CubeSat held along four corner rails, a PocketQube is cantilevered in its deployer by a single 1.6 mm thick sliding backplate. We derive the plate's flexural rigidity and fundamental modal frequency across Al 6061-T6, Al 7075-T73, Ti-6Al-4V and FR-4, and evaluate 3σ dynamic deflection under GSFC-STD-7000B (GEVS) random vibration.

  • Backplate
  • Structural dynamics
  • Natural frequency
  • Random vibration
  • GEVS
  • PocketQube
Engineering3 min read
DOC // NL-005(SQ-TN-2026-020)VECTOR -ZREV 0.1

CubeSat corner rail tribology, PC/104 stack mechanics and PQ9/CS14 backplanes

We examine the mechanical and electrical backbone of a CubeSat: the four 8.5 mm corner rails that interface with the deployer, the tribology of MIL-A-8625 Type III hard anodizing against vacuum cold welding, and the dynamic stiffness of a four-rod M3 PC/104 PCB stack compared against PocketQube 42×42 mm M2 stacks and the PQ9/CS14 backplane standard.

  • CubeSat
  • PC/104
  • Structures
  • Rails
  • Anodizing
Engineering2 min read

Subsystem matrix

Go straight to the subsystem entries of the encyclopedia. The values in each tile come from the same models as the tables in the entries.

Encyclopedia index

Solar cells, MPPT, Li-ion and LiFePO₄ batteries, orbit-average power budgets.

Orbit-average power, body-mounted cells, tumbling (Eq. 1 of the PocketQube review)
1P
0.55 W
1U
2.39 W
3U
5.71 W

One orbit at 525 km, 95.1 min

sunlit 59.5 min
eclipse 35.7 min
1P mean load
134 mW
Energy margin
284%
DoD per orbit
4.3%

Cell efficiency in the model

28%

Eclipse cycles per year

≈5,500

Links from VHF/UHF to X band, modulation choice, antennas and link budgets.

Small-satellite downlink bands, logarithmic frequency axis
100 MHz
300 MHz
1 GHz
3 GHz
10 GHz
VHF
UHF
S
X

PocketQubes and 1U CubeSats mostly use the 435–438 MHz amateur-satellite band; S and X band carry high data rates.

From magnetometers and sun sensors to star trackers; magnetorquers and reaction wheels.

m=−k B˙B\mathbf{m} = -k\,\dot{\mathbf{B}}_{\mathcal{B}}
B-dot law: a dipole opposing the rate of change of the field
1U: |ω| < 1°/s
5.4 min
1P: |ω| < 1°/s
87.8 min

Microcontrollers, FPGAs, radiation effects, RTOS and flight software frameworks.

  • MSP430FR16-bit, FRAM
  • STM32L4 / F4Arm Cortex-M4F
  • SAMV71Q21RTArm Cortex-M7
  • FreeRTOS
  • Zephyr
  • F Prime
  • cFS

Aluminium 6061/7075 frames, PCB structures, passive and active thermal control, MLI.

Property6061-T67075-T6
Yield strength276 MPa503 MPa
Thermal conductivity167 W/m·K130 W/m·K
SCC resistance (ECSS)HighLow
Density2.70 g/cm³2.81 g/cm³

Cold gas, water resistojets, electrospray and FEEP thrusters; Δv budgets.

Specific impulse ranges, logarithmic axis (NASA SoA 2026)
  • Cold gas40–110 s
  • Electrothermal20–350 s
  • Alternative mono- and bipropellant150–310 s
  • Electrospray and FEEP225–3,000 s
  • Pulsed plasma, vacuum arc87–3,200 s

Interactive tools

Engineering calculations that run in the browser and send nothing to a server.

Open the lab

Lab

Form factor comparator

Put three sizes side by side: volume, mass, mean projected area, orbit-average power, ballistic parameter, thermal time constant and lifetime from an altitude you choose.

1P
1U
3U

Lab

Mission index

125 missions, including the full 2013–2025 PocketQube census: launch, route to orbit, outcome, form factor and sourced status.

20032025
Active
23
Completed
7
Re-entered
27
Lost
10
Not verified
58

Lab

Link budget calculator

UHF and S-band downlink margin against elevation for any EIRP, data rate and ground station, with standard 1P and flight mission presets.

Reference 1P UHF (22 dBm, 9.6 kbit/s, 30° elevation)

4800 Bd
+3.1 dB
9600 Bd
+0.1 dB

Lab

Orbital lifetime calculator

Decay of a circular orbit with the Kennewell density model and the solar activity you set, with the five- and 25-year limits.

Fully loaded 1P, moderate solar activity

450 km
0.64 years
500 km
1.70 years
550 km
4.26 years