Encyclopedia

SatWiki

Entries on small-satellite formats, subsystems, engineering disciplines and operations. The tables are computed in the page from the same models as the research papers, and every entry lists its sources.

Form factors

  • SQ-FF-001

    PocketQube

    Picosatellite standard built from 50 mm cubic units (P). A 1P weighs at most 250 g, has one eighth of the volume of a 1U CubeSat and rides in its deployer on a sliding backplate instead of rails.

  • SQ-FF-002

    CubeSat

    Nanosatellite standard built from 10 cm units (U). Cal Poly’s CubeSat Design Specification defines the envelope, mass and centre-of-mass limits, rails and separation switches from 1U to 12U.

  • SQ-FF-003

    ThinSat

    Thin modules with a face close to that of a 1U CubeSat but only 1.25 cm thick. They fly in strings released into very low orbits and re-enter within days to two weeks.

  • SQ-FF-004

    TubeSat

    Picosatellite kit sold by Interorbital Systems: a sixteen-sided prism of circuit boards, 8.94 cm across and 12.7 cm long, weighing 0.75 kg, meant to fly on the company’s own rocket.

  • SQ-FF-005

    ChipSat (Sprite)

    Gram-scale satellites built on a single circuit board. Cornell’s 4 g Sprites were released by the hundred from the KickSat-2 carrier in 2019 and sent data from orbit; in 2025 a PocketQube hosted a ChipSat of its own.

  • SQ-FF-006

    CanSat

    Sub-orbital training device built inside a 66 × 115 mm beverage-can envelope (~350 g) and lofted by balloon, sounding rocket or drone to rehearse end-to-end satellite engineering.

  • SQ-FF-007

    CubeSat Design Specification (CDS Rev. 14.1) & PC/104 Architecture

    Mechanical, electrical, and operational requirements of Cal Poly’s CubeSat Design Specification Rev. 14.1 (1U–12U), corner rail tolerances, separation switches, and the 90×96 mm PC/104 avionics stack.

Subsystems

  • SQ-SS-001

    Electrical power system (EPS)

    Collects solar energy, stores it in a battery and regulates and distributes it to the other subsystems. In small satellites the budget is set by cell area, eclipse duration and battery cycle life, and a 1P lives on about half a watt.

  • SQ-SS-002

    On-board computer and data handling (OBC/CDH)

    Runs the flight software, executes telecommands, builds telemetry, stores data and manages the operating modes. Small satellites use commercial microcontrollers protected against radiation effects by software and hardware measures.

  • SQ-SS-007

    Passive magnetic attitude control (PMAC)

    A permanent magnet that aligns one axis with the geomagnetic field and soft-magnetic dampers that drain the spin. It needs no power, software or sensors, which is why most 1P PocketQubes use it, but its physics scales badly into a 50 mm cube.

  • SQ-SS-003

    Attitude determination and control (ADCS)

    Measures the orientation of the spacecraft and turns it where the mission needs it. From magnetometers and magnetorquers to star trackers and reaction wheels, small-satellite ADCS covers pointing from tens of degrees to arcseconds.

  • SQ-SS-004

    Communications (COMMS)

    Carries telemetry, telecommands and payload data between spacecraft and ground. Small satellites span VHF and UHF amateur bands, S, X and Ka band and optical links; the link budget decides whether a link closes.

  • SQ-SS-005

    Structures and thermal control (STR/TCS)

    The frame that carries launch loads, the mechanisms that deploy antennas and arrays, and the thermal design that keeps every part within its temperature range. Small-satellite frames are mostly machined aluminium; thermal control relies on surface finishes.

  • SQ-SS-006

    Propulsion (PROP)

    Changes or holds the orbit. Small satellites fly cold-gas, electrothermal, green monopropellant and electrospray thrusters; for PocketQubes, holding a low orbit needs micronewton thrust from a few tens of grams, a combination not yet demonstrated.

  • SQ-SS-008

    Payloads

    What small satellites carry: radios and spectrum monitors, cameras, laser-ranging reflectors, sensors, propulsion and materials experiments. In a PocketQube the payload competes for a few square boards, a fraction of half a watt and a downlink of kilobytes per pass.

  • SQ-SS-009

    Antennas & deployment mechanisms

    Quarter-wave and half-wave UHF tape-spring antennas, S-band patch arrays, UHMWPE thermal-knife hold-downs and deployment verification switches on picosatellites.

  • SQ-SS-010

    Batteries & energy storage

    Cylindrical 18650 and pouch lithium-ion / LiFePO4 cells for picosatellites: specific energy, vacuum pouch swelling, 0 °C charge protection and LEO cycle life.

  • SQ-SS-011

    Flight software & fault recovery

    State machines, real-time operating systems, brown-out bootloops, external watchdog hierarchies and non-volatile parameter storage on small satellites.

  • SQ-SS-012

    Telemetry framing & protocols

    AX.25, CubeSat Space Protocol (CSP), CCSDS reed-solomon/convolutional coding, Morse CW beacons and Kaitai Struct decoders for small-satellite downlinks.

Engineering

  • SQ-EN-001

    Materials and processes

    Which alloys, coatings, solders and polymers a small satellite can use, and why the answers change at PocketQube scale: the sliding backplate is interface-critical, eclipse cycling fatigues solder joints, and outgassing rules differ between standards.

  • SQ-EN-002

    Space environment

    What low Earth orbit does to a small satellite: a thermosphere whose density follows the Sun, atomic oxygen, trapped and solar radiation, a dipole-like magnetic field, strong thermal forcing and debris. PocketQubes feel each effect more strongly per kilogram.

  • SQ-EN-003

    Testing and qualification

    How a small satellite proves it will survive launch and work in orbit: model philosophy, vibration, thermal vacuum, bake-out, functional and deployment tests. Small teams test less than agencies, and the early failure statistics of CubeSats show what that costs.

  • SQ-EN-004

    Systems engineering & budgets

    Coupled mass, power, link, thermal, data and Δv margin management for PocketQubes and CubeSats from concept to flight readiness.

  • SQ-EN-005

    Radiation effects & COTS screening

    Total ionizing dose (TID), single-event upsets (SEU) and destructive latch-up (SEL) in the South Atlantic Anomaly for 500–600 km COTS avionics.

  • SQ-EN-006

    Reliability & failure statistics

    Empirical survival rates, dead-on-arrival root causes (EPS, antenna release, unknown TLE) and lessons from the 2013–2025 PocketQube census.

  • SQ-EN-007

    Magnetic cleanliness

    Controlling parasitic current loops, ferromagnetic fasteners and nickel-plated battery cases that otherwise dominate disturbance torques on 50 mm picosatellites.

Operations

  • SQ-OPS-010

    CubeSat Orbital Deployers (P-POD, ISIPOD, QuadPack, NRCSD & CSD)

    Mechanical architecture, door release mechanisms, ejection spring kinematics, and rail vs. canisterized clamping across P-POD, ISIPOD, Exolaunch EXOpod/QuadPack, NanoRacks NRCSD, and Rocket Lab CSD.

  • SQ-OP-001

    Launch and deployment

    How small satellites reach orbit: from a host satellite, directly from the launch vehicle or from an orbital transfer vehicle. For PocketQubes the launch segment has been a major cause of loss, with 13 of 77 units lost or degraded before operations.

  • SQ-OP-002

    Ground segment

    The stations, networks, software and people that talk to a satellite. Small missions combine their own station with open networks such as SatNOGS; a mid-latitude station sees a 525 km Sun-synchronous orbit about three times a day above 10°.

  • SQ-OP-003

    Regulation and debris mitigation

    Spectrum coordination, licensing and the end-of-life rules that decide where a small satellite may fly. The FCC five-year rule and the older 25-year guideline translate directly into altitude ceilings for spacecraft without propulsion.

  • SQ-OP-004

    Frequency coordination & licensing

    ITU Radio Regulations, IARU amateur-satellite coordination, national administration filings (API/CR/N) and UHF/S-band allocations for PocketQubes and CubeSats.

  • SQ-OP-005

    LEOP & in-orbit commissioning

    Launch and Early Orbit Phase (LEOP) sequence: ejection inhibit timer, antenna deployment, first beacon acquisition, battery/thermal verification and payload checkout.

  • SQ-OP-006

    Tracking, TLEs & spacecraft identification

    NORAD/COSPAR cataloguing by the 18th Space Defense Squadron, SGP4 orbital elements (TLE/OMM), radar cross-section of 5 cm cubes and Differential Doppler identification.

  • SQ-OP-007

    Launch market, brokers & orbital transfer vehicles

    How PocketQubes and CubeSats buy rides to orbit: dedicated rideshare missions, turnkey launch brokers, orbital transfer vehicles (OTVs) and historical routes.

Missions