Talking to Space Shuttle Atlantis

Serge Stroobandt, ON4AA

Copyright 2001–2016, licensed under Creative Commons BY-NC-SA

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This is a summary of my 2m FM radio contact on Saturday, March 28, 1992 with astronaut and fellow radio amateur David C. Leestma, N5WQC, on board of spaceship Atlantis during shuttle mission STS-45. This was also the mission that carried Dirk Frimout, ON1AFD the first Belgian astronaut into space. At that time, I was an eighteen year old first-year undergraduate engineering student and I held the call sign ON1ASP. I was one of the only 48 Belgian hams fortunate enough to make a QSO with STS-45.


Note: For the duration of the mission, all four ham-licensed astronauts shared David Leestma’s call, N5WQC.

description recording
Dirk Frimout, ON1AFD calling CQ. [ogg][mp3]
Wilfried Suffis, ON7TH calls. Dirk Frimout, ON1AFD answers. Coincidentally, both are from Poperinge, Belgium. [ogg][mp3]
Dirk Frimout, ON1AFD saying that he also studied at Ghent University. [ogg][mp3]
Me calling with call sign ON1ASP. David Leestma, N5WQC confirms. [ogg][mp3]
Kathyrn Sullivan, N5YYV coming back to a LM5-station. [ogg][mp3]
Kathyrn Sullivan, N5YYV answering a call from Norwegian club station LA2AB. [ogg][mp3]


SAREX patchThe SAREX patch
The Shuttle Amateur Radio Experiment (SAREX) was a long-running program to use amateur radio equipment on board NASA’s Space Shuttle, the Russian Mir space station, and the International Space Station. It involved students in exchanging questions and answers with astronauts on orbit. More than 200 schools participated. It was also used to conduct communications experiments with amateur radio operators on the ground. Detailed information about SAREX can be found here. The SAREX experiment has been superseded by the Amateur Radio on the International Space Station (ARISS) program.

SAREX was designed to demonstrate the feasibility of amateur shortwave radio contacts between the Space Shuttle and ground amateur radio operators. SAREX also served as an educational opportunity for schools around the world to learn about space first hand by speaking directly to astronauts aboard the Shuttle via ham radio. Contacts with certain schools were included in planning the mission.

In addition, when the Russian Mir Space Station became visible to the STS-45 crew during the mission, SAREX was used to make a conversation with the Mir cosmonauts, who also had a ham radio aboard.

Four of the STS-45 crew members are licensed amateur radio operators: Mission Specialists Dave Leestma, call sign N5WQC; Kathy Sullivan, call sign N5YYV; Pilot Brian Duffy, call sign N5WQW; and Payload Specialist Dirk Frimout, call sign ON1AFD. Frimout and Sullivan are fluent in several European languages and made contacts in that part of the world. However, STS-45’s 57-degree inclination placed the spacecraft in an orbit that allowed worldwide contact possibilities, including high latitude areas not normally on the Shuttle’s groundtrack.

Ham operators could communicate with the Shuttle using VHF FM voice transmissions, a mode that made contact widely available without the purchase of more expensive equipment. The primary frequencies used during STS-45 were 145.55 MHz for transmissions from the spacecraft to the ground and 144.95 MHz for transmissions from the ground to the spacecraft.

SAREX was flown previously on Shuttle missions STS-9, STS-51F, STS-35 and STS-37. The equipment aboard Atlantis for STS-45 included a low-power, hand-held FM transceiver, spare batteries, a headset, an antenna designed to fit in the Shuttle’s window, an interface module and an equipment cabinet.

SAREX was a joint effort of NASA, the American Radio Relay League (ARRL), the Amateur Radio Satellite Corp. and the Johnson Space Center Amateur Radio Club. The Goddard Space Flight Center Amateur Radio Club will operated 24 hours a day during the mission, providing information on SAREX and retransmitting live Shuttle air-to-ground communications.

STS-45 SAREX operating frequencies
location shuttle TX (MHz) shuttle RX (MHz)
U.S., Africa, South America and Asia 145.55 144.95
145.55 144.97
145.55 144.91
Europe 145.55 144.95
145.55 144.75
145.55 144.70

My equipment


STS-45 crew photo with, from left to right, in front: pilot Brian Duffy and commander Charles F. Bolden Jr.; backed by payload specialist Byron K. Lichtenberg, mission specialist C. Michael Foale, mission specialist David C. Leestma, payload commander Kathryn D. Sullivan and payload specialist Dirk D. Frimout. Image credit: NASA

STS-45 crew photo with, from left to right, in front: pilot Brian Duffy and commander Charles F. Bolden Jr.; backed by payload specialist Byron K. Lichtenberg, mission specialist C. Michael Foale, mission specialist David C. Leestma, payload commander Kathryn D. Sullivan and payload specialist Dirk D. Frimout. Image credit: NASA

name call function mission
Charles F. Bolden Jr. Commander 3rd
Brian Duffy N5WQW Pilot 1st
Kathryn D. Sullivan N5YYV Payload Commander 3rd
David C. Leestma N5WQC Mission Specialist 2 3rd
C. Michael Foale Mission Specialist 3 1st
Byron K. Lichtenberg Payload Specialist 1 2nd
Dirk D. Frimout ON1AFD Payload Specialist 2 1st

Notable facts:


Space shuttle hardware

Space shuttle hardware


The launch was originally scheduled for March 23, 1992 but was delayed one day because of higher than allowable concentrations of liquid hydrogen and liquid oxygen in the orbiter’s aft compartment during tanking operations. During troubleshooting, the leaks could not be reproduced, leading engineers to believe that they were the result of plumbing in the main propulsion system not thermally conditioned to the super cold propellants. The launch was eventually rescheduled for March 24.

STS-45 trajectory sequence of events
event t (m:s) vrel. (km/h) mach altitude (m)
Launch 00:00 0 0.00
Begin roll maneuver 00:10 201 0.16 237
End roll maneuver 00:19 459 0.37 1 084
SSME throttle down to 89% 00:22 548 0.45 1 460
SSME throttle down to 67% 00:31 788 0.64 2 927
Max. dyn. pressure (max Q) 00:56 1 365 1.11 9 321
SSME throttle up to 104% 01:06 1 688 1.38 12 907
SRB separation 02:05 4 544 3.71 47 270
Main engine cutoff (MECO)* 08:35 27 433 22.39 114 811
Zero thrust 08:41 27 431 22.39 114 882
ET separation 08:53
Orbital Manoeuvring System OMS-2 burn 37:08

Table notes:


STS-45 vehicle and payload weights
description mass (kg)
Orbiter (Atlantis) empty and 3 SSMEs 78 151
Cargo bay payloads
Atmospheric Laboratory for Applications and Science-1 (ATLAS-1) 15 100
Shuttle Solar Backscatter Ultraviolet Instrument (SSBUV-4) 6 849
Get-Away Specials (GAS) Canisters & Support Equipment 237
Middeck payloads
DSOs/DTOs 113
Space Tissue Loss (STL) 31
Shuttle Amateur Radio Experiment (SAREX) 14
Radiation Monitoring Experiment-III (RME-III) 10
Investigations into Polymer Membrane Processing (IPMP) 7.7
Visual Function Tester-II (VFT-II) 4.5
Cloud Logic to Optimize Use of Defense Systems (CLOUDS-1A) 2.3
Total Vehicle at SRB Ignition 2 039 311



STS-45 crew patchSTS-45 crew patch
The mission carried the first Atmospheric Laboratory for Applications and Science (ATLAS-1) on Spacelab pallets mounted in the orbiter’s cargo bay. The non-deployable payload, equipped with 12 instruments from the U.S., France, Germany, Belgium, Switzerland, the Netherlands and Japan, conducted studies in atmospheric chemistry, solar radiation, space plasma physics and ultraviolet astronomy.

ATLAS-1 instruments were:

Other payloads included Shuttle Solar Backscatter Ultraviolet (SSBUV) experiment, one get-away Special (GAS) experiment and six mid-deck experiments. The mission was extended by one day to continue science experiments.


STS-45 landing at Kennedy Space Center, Florida. Image credit: NASA

STS-45 landing at Kennedy Space Center, Florida. Image credit: NASA

QSL card

Some time after my contact, my mother told me we had received a white envelope with NASA letterhead. In it, was this very nice QSL card, signed by Dave Leestma, N5WQC. Astronaut Dirk Frimout also so kind to sign the card after a talk he held at a local female service club that my mom attended.

QSL card signed by Dave Leestma, N5WQC and Dirk Frimout

QSL card signed by Dave Leestma, N5WQC and Dirk Frimout


Professor CalculusProf. Calculus
Dirk Frimout’s flight as Belgium’s first astronaut made him instantaneously very famous in Belgium and triggered what was called Frimout-mania. Frimout’s striking resemblance with the fictional character Professor Cuthbert Calculus of the also Belgian comics series The Adventures of Tintin, his goofiness and his high-pitched voice strengthened this frenzy. Philippe of Belgium also talked with Frimout during the mission and a ticker tape parade was organised when he came back to Belgium.


Dirk Frimout’s brother is a graphical artist. He made several drawings about his brother’s space flight.

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