LOWDOWN - Australia's History in Satellite Technology

The Lowdown

Australian Space development in focus

Australia in Space, its history and it's future, links, comments and opinion.

Australia's Satellites & Programs > WRESAT

WRESAT was the first Australian-made satellite to be launched into space, made in 1967 and launched from Woomera late that year.

Project SPARTA

The Americans had been utilizing the facilities of Woomera to conduct tripartite research (United States, Australia and Britain) into the physical effects of high-speed re-entry of warheads, an activity known as Project SPARTA.

Project SPARTA utilized three-stage launch vehicles, the first stage being the highly successful Redstone rocket with the second and third stages being solid-propellant based.

Nine SPARTA launch vehicles (and one spare) were sent to Australia for use in the project. However, since no launch failures occurred the spare SPARTA launch vehicle was not going to be used. The options were either use it or return it to the United States where it could quite possibly have ended up on a rubbish dump..

Broad hints turned rapidly into ideas which quickly came concrete proposals. Funding was secured, not necessarily because of the sound arguments presented to the government of the day on how useful the WRESAT experience would be for upcoming trials but most likely because it was a cheap way to get some national prestige.

WRESAT Design

WRESAT design

Design Concept

Very early on in the WRESAT project it was decided that for simplicity WRESAT would be integrated directly into the SPARTA third stage. In order to achieve an accurate orbital insertion the combined second and third stage was spun to approximately two revolutions per second. The WRESAT 'package' was a little over two metres long and weighed approximately 72.5 kg. WRESAT was battery powered and thus would only operate for a short period of time in space.

WRESAT WRESAT under construction

An interesting point to note about the WRESAT design is that, even though WRESAT was spinning around its long axis at orbital insertion, this was not the preferred orientation for the scientific payload. Close inspection of the WRESAT schematic to the right shows an energy dissipator which was a closed hydraulic loop of silicone oil which dissipated the rotational energy as heat. The net result is WRESAT eventually tumbling around it's short axis which places the axis of rotation pointing out into space.

Scientific Payload

testing

WRESAT carried scientific instruments which were very similar to those carried on sounding rockets already being used at Woomera. As such, these sensors were predominantly for upper atmospheric research. There were sensors to measure solar radiation, specifically three wavelengths which had the greatest impact on the temperature and composition of the upper atmosphere. The same sensors could also measure the temperature of the solar atmosphere and the density of molecular oxygen in the Earth's atmosphere. Additionally, there was a small telescope with a lithium fluoride lens which could measure the faint ultraviolet halo (GeoCoronal) that surrounds the Earth at night.

Launch and Operation

WRESAT on the launch pad

WRESAT was launched on 29 November 1967, atop the spare SPARTA launch vehicle, from Woomera's Launch Area 8, the same pad as used for the nine Project SPARTA launches. The launch track was polar, slightly east of due-north, the same as the ELDO F4.

WRESAT launching

The launch was successful with WRESAT entering an elliptical polar orbit and becoming operational. However, with only batteries to provide power, WRESAT operated for only two weeks. The low perigee of the orbit, 198 km, also meant that the orbit would degrade rapidly; WRESAT re-entered the atmosphere on 10 January 1968 and burned up. Thus, the first Australian satellite to orbit (Australis-OSCAR 5 was actually built before WRESAT but not launched until 1970), lasted just 43 days in orbit.

The satellite re-entered over the Atlantic Ocean west of Ireland at 11:34 GMT on 10 January 1968. It had completed 642 orbits and transmitted scientific data for 73 orbits. The first stage of the launch vehicle fell in the Simpson Desert of central Australia, while the second stage came down in the Gulf of Carpentaria. Little of the second stage would have survived re-entry.

Historical Postscript

Woomera township volunteers recovered the first stage of the WRESAT launcher from the Simpson Desert in April 1990. The battered, but surprisingly intact, vehicle is now on display in the rocket park opposite the Woomera Heritage Centre.

There were no follow-on WRE satellite and WRESAT was to be, and remains, an orphan.

Specifications

Name: WRESAT
Designation: 03054/67118A
Purpose: Upper atmosphere research
Launched: 29 November 1967
Perigee/Apogee: 198 / 1252 km
Inclination: 83.3 degrees
Period: 99.3 minutes
Mass at launch: 50 kg (72 kg including the integrated 3rd stage)
Length: approx 2 metres
Re-entered: 10 January 1968

References:

Peter Morton, Fire Across the Desert, Chapter 24

Back to the main index