Två nya Cubesats med amatörradio finns ombord STS-116, alltså den rymdfärja som Christer Fuglesang åker upp med.
December 7 STS-116 Launch Includes Three Amateur Satellites
Space Shuttle Discovery is scheduled for launch on December 7 at
9:35 PM EST (UTC-5). During the 12-day mission and three spacewalks,
the crew will work closely with flight controllers at NASA’s Johnson
Space Center, Houston, to install a new segment of the station’s
girder-like truss and activate the station’s permanent, complex power
and cooling systems.
The Shuttle will also carry to orbit three new satellites, RAFT-1,
MARSCOM and ANDE, designed, built, and tested by the Midshipmen of
the US Naval Academy’s Satellite Laboratory in Annapolis, Maryland.
The primary mission of the RAFT satellite is tied to the calibration
of the US Navy Space Surveillance Radar which is the primary source of
ALL satellite tracking data for ALL spacecraft in the USA. Data from
this radar is what helps generate the Keplarian Elements used by all
Amateur Satellites operators.
The secondary mission of RAFT and MARScom are to provide packet digital
communications relay for mobile units to transmit their GPS coordinates
and messages via the satellites. This is a continuation of the PCsat,
PCSAT2 and ARISS missions. The downlink is received by a global system
of volunteer ground stations that feed the pcsat.aprs.org live web page.
The primary limitation on single channel LEO satellite communications
is the congestion on the uplink. The RAFT Packet-to-Voice transponder
solves this problem by compressing the uplink into a single 1 second
burst per station, and then expanding it to voice for the FM downlink.
This way, students with nothing but a scanner receiver can hear all of
the downlink communications (voice) yet the uplinking stations have a
very low probabilty of collision due to the short duration of the uplink.
A voice synthesizer converts the packet to voice.
ANDE was developed by the Naval Research labs as an "Atmospheric Neutral
Density Experiment" to measure the decay from orbit of a perfectly spher
ical 18" ball. Hearing that it was empty, the Naval Academy under the
mentoring of Bob Bruninga, WB4APR, proposed an amateur radio transponder
for the inside.
There can be no external antennas and no solar panels or anything that
would disturb the aerodynamic performance of the very smooth sphere. The
spherical satellite is split in half with an insulator and uses the
space frame as the antenna for the 2 meter system. There are 112
Lithinum primary "D" cells inside the sphere to power it for a year.
To keep the current drain to a minimum, the ANDE comms payload sleeps
90% of the time, only waking up once every 16 seconds to listen for
packets. Hearing none, it goes back to sleep to convserve power. If
packets are heard, then it remains awake and serves as an APRS packet
digipeater until 1 minute after the last packet. In addition, ANDE has a
voice synthesizer and can speak packets addressed to it.
The telemetry from the satellite will be of a similar form to that of
PCSAT and PCSAT2 and will be distributed by the APRS-IS network. Dave,
G4DPZ has been working on the telemetry web site. Details of the URL
will be published after launch.
The RAFT-1 and ANDE satellite downlinks will be 145.825 MHz. The MARS
frequencies used by MARSCOM are on Navy-Marine Corps MARS frequencies.
For full technical details please refer to:
http://www.ew.usna.edu/%7Ebruninga/ande-raft-ops.html