How the ATV hatch stays open

We checked in with Lionel Ferra, at EAC Cologne, and asked him for some background on a couple of his recent tweets:

and

Lionel sent in today's guest post, describing details on how the hatch procedures have involved during the ATV missions.

What is so peculiar about the way ATV-5 hatch was fixed by Alexander Gerst? Over the course of five ATVs, we have developed and upgrade several times the On-board Data Files (ODF), or procedures. Those documents are user manuals for any equipment on board, from operating an experiment to docking ATV.

A part of the attached phase procedure for ATV is to permanently fix the hatch so that the crew can enter and exit ATV easily while enabling a quick closure in case we experience an emergency on board ISS or if it has to be closed for planned operations like the Russian EVA of last week.

Initial ATV hatch fixation, here at the beginning of ATV-2 mission. Credit: ESA/NASA

Initial ATV hatch fixing, here at the beginning of the ATV-2 mission. Credit: ESA/NASA

Back in 2011, when ATV-2 docked (see hatch above), it was quickly discovered that the hatch fixing strategy adopted for ATV-1 was not sufficiently stiff. Any time the crew entered and exited ATV-2, the delicate conical part of the docking system – and thus the hatch – bumped on one of the rods at the front part of the pressurized volume.

What simply needed to be done was to stiffen that attachment with more Velcro or straps avoiding this tiny wobble movement.

Indeed, a small dent was observed on the ATV-2 docking system after a few weeks in orbit due to this. This metal deformation was per se not a major issue but could have had some consequences in case ATV-2 would have to undock and then redock. All ATVs have been programmed and ground teams trained to execute this (unlikely) manoeuvre.

Nonetheless, ESA Astronaut Paolo Nespoli was asked to figure out a way to 'rigidify' the strapping while still not hindering a fast closure of the hatch. This was extensively photographed and filmed for the ground teams so that they could update the specific section of the ODF to reflect this new approach from ATV-3 onwards.

ATV5 ODF Hatch Fix extract

ATV5 ODF Hatch Fix extract

For various reasons, the ATV-3 hatch did not show the same signs of wobbling, so this standard easy fix was sufficient, as well, for ATV-4.

But the ‘Paolo’s procedure’ remained as part as the normal operations (as the traditional ATV-1 fixing method might again be potentially wobbling – see figure above). For ATV-5, Alexander Gerst and his fellow crew mates attached the hatch like for ATV-2 (see figures below).

We still yet don’t know if the easy fixing done for all other ATVs would have been sufficient; this would be a typical question for the debrief session once Astronaut Alex Gerst is back on Earth later this year.

Current ATV-5 Hatch configuration, 29 August 2014. Credit: ESA/NASA

Current ATV-5 Hatch configuration, 29 August 2014. Credit: ESA/NASA

Current ATV-5 Hatch configuration, 29 August 2014. Credit: ESA/NASA

Current ATV-5 Hatch configuration, 29 August 2014. Credit: ESA/NASA

 

Posted in ATV team, ATV-5, Hatch opening/closing, Images, News and updates, Technology & engineering | Tagged , , , | 1 Comment

ATV-5 reboost complete

Here is an update on today's ATV operations just delivered by Thomas Beck at ATV-CC.

Today's reboost of the ISS by ATV-5 has been carried out successfully. 

ATV's main thrusters (M1 and M3) were ignited today at 08:37:00 GMT (10:37:00 CEST) and burned for 179 secs using 58.7 kg of propellant. The manoeuvre increased the ISS velocity by 0.43 m/sec as measured by on-board accelerometers.

Note that the precise manoeuvre accuracy determination will be carried out by MCC-M (Moscow) under whose authority ATV reboosts of the entire ISS by visiting vehicles are carried out.

Posted in ATV-5, ATV-CC, Flight dynamics, ISS, ISS Partners, News and updates, Operations | Tagged , , | Leave a comment

Here’s the plan: ISS reboost 27 Aug

Tomorrow, ATV Georges Lemaître conducts the first full reboost of the ISS since arrival at the station on 12 August. (The reboost done on 14 August was just a test....)

Here are the planned parameters, send in by ESA Mission Director Thomas Beck at ATV-CC. Remember: these are just what's planned and the actual numbers may vary.

  • Date: 27 August 2014
  • Delta-v: ~0.4 m/s
  • Time of ignition (Tig): ~08:37 GMT / ~10:37 CEST
  • Duration: 5 minutes
  • Planed back-up slot, if needed: 29 August

 

Posted in ATV-5, ATV-CC, Flight dynamics, ISS, Mission reports, Operations | Tagged , | Leave a comment

Mission diary: post-docking happenings at ATV CC

Credit: Roscosmos/O.Artemyev

Credit: Roscosmos/O.Artemyev

After the flawless docking on 12 August, things certainly quietened down a bit at ATV CC, but our work was far from over.

Editor’s note: Blog post contributed by ESA’s Charlotte Beskow

 13 Aug Wednesday

The crew entered the ATV for the air scrubbing activity — cleaning the air that is inside the atv. The hatch was closed after this activity.

 Aug 14 Thursday

The ISS was reboosted by the ATV in a test reboost, which let our Russian colleagues check the nominal operation of the ATV thrusters. Everything was working as expected.

It is never easy to follow the crew activities inside ATV. We don’t have direct communication with them (ATV has no on-board communication link for crew) but over the years we have learned watch what is happening inside ATV by watching the thermal readings.

Credit: Roscosmos/O.Artemyev

Credit: Roscosmos/O.Artemyev

In fact, if I was to redo my studies, I think I would become a thermal engineer. It is amazing what thermal engineers can deduce from what seems like a very basic piece of information.

The next activity involved the crew entering the ATV again, to set it up for the nominal attached phase of operations. Well, almost nominal.

Due to an issue on the cargo belts, the direction of the airflow between SM and ATV was modified and some special filters were installed. This was a very successful solution, one which we planned and put into place very efficiently.

Consequently the EST (ATV Engineering Support Team) specialists were glued to their screens, analysing every little variation in fan speed and temperature. We also relied on a few other, probably unexpected, readings like the changing state of the pressure valves on board ATV.

Aug 15 Friday

This was a ‘quiet day’. The only thing we had to observe was the feathering of ATV Solar Arrays when Cygnus departed the ISS. This is done to protect them in case the departing vehicle suddenly and rapidly accelerates.

Aug 16 Saturday

Credit: Roscosmos/O.Artemyev

Credit: Roscosmos/O.Artemyev

This was a very quiet day, as in relatively silent despite how busy we were. The teams in ATV CC patched the ATV SW (software). Normally there is quite a lot of talking during operations but on this morning everyone present was 100% concentrated on the procedure.

It was a first for us. The FAS (Flight application software)) patch process had been validated in an end-to-end  system validation test before the first flight. This particular patch had been validated in Les Mureaux only a week before this activity at the test facilities there, and now we were doing it on the vehicle.

As with most things that have been very well prepared, this went incredibly smoothly. The patch was tested again on the 18 August during the propulsion activation for CMG (Control Momentum Gyros).

Aug 17 Sunday

Towards the end of the afternoon we were back in ATV CC. Crew were ready to close the ATV and ISS hatch in preparation for the upcoming Russian space walk (EVA) on 18 August.

This is a standard procedure, but it meant configuring ATV so that it could undock from the ISS if necessary. We were again glued to our screens—reading heat and pressure, following as best as we could what was happening.

At the end of the day ATV was closed, the fan was OFF and the inert hatch vestibule (the space between ISS and ATV hatches) depressurised.

Aug 18 Monday

Credit: Roscosmos/O.Artemyev

Credit: Roscosmos/O.Artemyev

This was the day of the Russian EVA. ATV was activated to provide propulsive support in case it became necessary to desaturate the CMGs (Control Momentum Gyros) used to maintain ISS attitude.

The EST was present in force, eager to see that the SW patch had worked. The four chains of the propulsion system were activated nominally and then we waited. After many hours, ATV was returned to dormant mode.

The propulsion chain had not been used. Never mind. With the activation of the four chains we knew the patch had worked. The quiet evening also gave us the nice opportunity to celebrate the birthday of one of our EST team members.

Aug 19 Tuesday

The crew entered the ATV and set it up for the attached phase operations. By the time this was complete, the crew day was already over. Because of time constraints, and our planned cargo activities the following morning, we all agreed to postpone the reverse airflow procedure.

Aug 20 Wednesday

The crew unloaded more cargo from the ATV and complimented us on the cleanliness of our vehicle, after which they set the airflow configuration back to nominal mode.

At the end of this day, eight days after docking, we were proud to say that ATV was now returned to a completely nominal configuration.

Charlotte Beskow- ATV CC

 

Posted in ATV-5, ATV-CC, Docking, ISS | Tagged , , , , , , , , , | Leave a comment

ATV-5 delivers space joystick

NASA's Space Station Live commentator Rob Navias talks with Dr. Andre Schiele, head of the European Space Agency's telerobotics lab at ESTEC, about the Haptics-1 experiment that arrived at the International Space Station aboard ATV-5. The Haptics-1 study involves the installation of a highly advanced joystick on the space station, designed for the study of remote control of robots on Earth by astronauts in space.

Posted in Astronauts, ATV-5, Cargo, ISS, ISS Partners, News and updates, Technology & engineering, Video | Tagged , , , | Leave a comment

Does orbital speed really increase?

We saw a tweet earlier today from @DrHughLewis:

As with many tough, technical questions, we passed this to the ATV-CC flight dynamics experts! The reply below was provided by Arnaud Boutonnet (Thanks, Arnaud!).


 

Let us assume that the orbit of the ISS is initially circular.

When a reboost is performed, the speed increases and the orbit becomes slightly elliptical. The point where the boost is performed is the perigee, the point with the lowest altitude, which turns out to be the initial altitude.

The opposite point on the orbit is the apogee, the point with the highest altitude; therefore at this point the altitude is larger than the initial altitude. However orbital mechanics dictate that at this point the speed will have been reduced; it will actually be smaller than the speed on the initial orbit before the reboost!

But the orbit of the ISS can be circularised at the higher altitude by performing a second reboost at the apogee of the (new) elliptical orbit; therefore the ISS will be at a higher altitude. And here comes the trick! As said above, the speed at apogee is smaller than the speed on the initial orbit. And even after the second reboost, it is still smaller.

Conclusion: after two reboost manoeuvres, which both increased the speed, the ISS ends up at a higher altitude with a lower speed compared to the initial orbit. Interesting, no?

Posted in ATV team, ATV-5, Flight dynamics, News and updates, Technology & engineering | Tagged , , | 2 Comments

Reboost test complete

Just received this from ESA Mission Director Thomas Beck, on console today at ATV-CC, Toulouse.

The first reboost of the ISS by ATV-5 has been carried out successfully.

The freighter's main thrusters M1 and M3 were ignited today at 18:58:00 CEST (16:58:00 GMT) and burned for 469 secs using up 151.6 kg of propellant. The manoeuvre increased the ISS's velocity by about 1.1 m/sec.

Posted in ATV-5, ATV-CC, Flight dynamics, ISS, Mission updates, Operations, Video | Tagged | 2 Comments

More ingress!

Some of the latest photos sent down by the crew!

iss040e091991

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

ATV-5 ingress. Credit: ESA/NASA

Posted in Astronauts, ATV-5, Cargo, Hatch opening/closing, Images, News and updates | Tagged , | Leave a comment

Ingress

This morning, the ISS crew led by ESA astronaut Alexander Gerst are conducting the final ingress activities. After shutting down then removing the scrubbing equipment, the astronauts can spend a bit of time exploring this new, integral addition to the ISS working space and its massive cargo stores! Note that Alex is wearing a mask (and cool space goggles!), a final safety precaution to avoid breathing any final bits of debris left in the atmosphere.

More photos of ingress from this morning in Alex's Flickr channel.

Posted in Astronauts, ATV-5, Cargo, Docking, Hatch opening/closing, Mission updates, Technology & engineering | Tagged , , | Leave a comment

Most.Amazing.ATV.Pics.Ever

Some of the most amazing ATV photos we've ever seen now posted live in the blog of Expedition 40 crew member, Russian cosmonaut Oleg Artemyev. Very, very well done!!!

Posted in Astronauts, ATV-5, Docking, Images | Tagged , , | Leave a comment