ChipSat (Sprite)

Definition

A ChipSat squeezes every function of a satellite (power, sensing, computing and radio) onto one small circuit board. The best-known example is the Sprite, developed at Cornell University under Mason Peck: a board of about 3.5 cm that weighs 4 grams[1].

The KickSat missions

To carry Sprites into orbit, the KickSat project led by Zachary Manchester built a 3U CubeSat carrier, funded through a crowd-funding campaign[2]. The first attempt, KickSat-1, was launched on SpaceX CRS-3 on 18 April 2014, but a radiation-induced reset of its master clock pushed back the release timer, and the carrier re-entered on 14 May 2014 without releasing its Sprites[3].

KickSat-2 launched on Cygnus NG-10 on 17 November 2018, separated from Cygnus at about 300 km on 13 February 2019 and released 105 Sprites on 18 March 2019. The first signals arrived the following night, and the Sprites re-entered within days, as designed[3].

A ChipSat on a PocketQube

In January 2025 the 185 g PocketQube POQUITO of the University of Luxembourg carried an independent ChipSat and demonstrated the first visible-light link between a PocketQube and a ChipSat[4]. The mission pairs the two smallest classes: the PocketQube provides power, radio and attitude, the ChipSat a free-flying node a few grams heavy[5].

Why it matters

The Sprites showed that the parts cost of a satellite can fall below a hundred dollars and that many nodes can be released at once and heard on a single channel. The approach points to multi-point networks for atmospheric and space-weather measurements, and to disposable probes in planetary exploration.

Sprite

Link budget

A milliwatt transmitter can close a link from LEO only at very low data rates and with spread-spectrum processing gain. Compared with the 0.5 W of a typical 1P transmitter the gap exceeds 20 dB, which means a data rate more than a hundred times lower for the same margin. The link budget article shows how each term scales.

Tracking

A board a few centimetres across is far below the size that LEO radars track routinely. The KickSat-2 Sprites were therefore released very low and re-entered within days; long-lived ChipSat missions raise regulatory concerns about tracking and collision risk.

Form factor	Mass (kg)	Ballistic parameter (m²/kg)	From 250 km	From 300 km	From 350 km	From 400 km
Sprite	0.00	0.3946	< 1 days	< 1 days	2 days	7 days
1P	0.25	0.0330	2 days	9 days	28 days	3 months

Kennewell density model, drag coefficient 2.2, mean tumbling area A_tot/4, re-entry at 180 km, spacecraft at the mass limit of its standard. Solar activity: low F10.7 = 70 sfu, Ap = 6; moderate 140 sfu, Ap = 12; high 210 sfu, Ap = 18.

Attitude and power

Sprites have no attitude control. As the board turns, both the solar input and the antenna gain change continuously, so the mission must work with intermittent power and an intermittent link.

Radiation

KickSat-1 showed that a single controller without redundancy can lose a whole mission to one radiation-induced reset. Even at the gram scale, critical timers deserve an independent hardware path.