posted 05-03-2025 02:23 AM               

Space Cover 804: Spacelab 3 Houston two cancels

Challenger space shuttle mission STS-51B (Spacelab 3) was launched from Kennedy Space Center on April 29, 1985 at 12:02:18 pm local time. The launch, originally scheduled for 12 noon, was delayed by 2 minutes and 18 seconds as consequence of a minor issue in the launch process. For this reason, space covers with KSC postmark bear a correct PM time slug on April 29, 1985.

As time difference between Florida and Texas states is one (1) hour, all space covers regarding launch event postmarked in Houston bear a very correct AM time slug on April 29, 1985.

However, I am still thinking on the second Houston cancel. Why a second Houston cancel with same date than previous one? Just to show two different cancels on same cover? Or there is a reason for this second cancel?

Normally, combo covers, i.e. covers with two or more cancels refer to launch and landing event and is appreciated if they are applied on different locations.

But why a cancel with same date, same place and same time slug? Again, just to show two different kind of cancels on same cover? Or it was an error?

Sometimes I have seen covers with a second cancel which refer to rocket/capsule/shuttle has achieved/entered into Earth orbit, or is deploying a satellite but this is not the case because Spacelab activation occurred 2 hours and 10 minutes later than launch and NuSat satellite was deployed at 4:15 pm. So, in both cases Houston hand cancel should bear PM time slug.

Another option could be that this Houston hand cancel refers to time in which Houston takes the total control of the mission. It is necessary to know that usually launch phase from KSC spends around 90 minutes (1 hour and 30 minutes). Again and according to this, Houston hand cancel should bear PM time slug.

Then, why this second Houston hand cancel AM time slug?

An open space to all your comments, suggestions and/or information will be welcomed. Thanks.

posted 05-09-2025 02:46 PM               

While I can't answer your question about the two Houston cancels on your cover, I can provide two more covers with Houston cancels and cachets relating to the activation of two Spacelab 3 experiments.

One cover is dated for the activation of the Crystal Growth Experiments carried out by Payload Specialist Lodewijk Van den Berg on April 30, 1985 and the other cover, dated May 2, for the activation of the Drop Dynamics Module carried out by Payload Specialist Taylor Wang.

These covers have interesting cachets, but for me, of unknown origin.

Of possible added interest, are these two STS-51B covers autographed by the two Spacelab 3 Payload Specialists, Dr. van den Berg and Dr. Wang. Dr. van den Berg has passed away at age 90 in 2022. In 1987, he autographed this cover in person for Ken Havekotte.