Wednesday, December 17, 2008

Thursday, November 20, 2008

New MIRIAM photos

Two new composite images taken during the MIRIAM mission were released today:

This image is an approximate view of what the human eye would have seen during the flight. It shows the MIRIAM Service Module high above Sweden as seen by the Camera Module on top of the REXUS-4 payload section. Since the individual images were taken over a period of several seconds, the relative position and state of individual objects is not correct. The second stage motor can be seen dropping away left from the center of the image, while the Service Module's jammed clamp ring is still attached.
The image capture sequence is from far left to far right.
The individual frames were captured by the Camera Module's solid state video camcorders. Lens distortions ("pillowing") were not corrected, which is why the curvature of the horizon does not match on either side.

This image shows the REXUS-4 Payload section with the still attached second stage motor. It was assembled from frames captured by the left-hand TV-boom-camera on board the Servce Module (the left-hand boom is the red one pointing upwards and towards the observer in REXUS4 Mosaic 02.jpg).

The differences in shades in both images result from the camera's adaptive exposure time, which leads to some frames being darker than others.

Image Rights: The Mars Society Germany and the University of the Federal Armed Forces of Germany, Munich.

Wednesday, November 5, 2008

MIRIAM Official Account

An official account of the MIRIAM mission has been released by Hannes Griebel, the lead systems engineer of Archimedes. With his permission, I am mirroring the article below. The message also includes some pictures of the mission taken from space, about 175km above Earth.


Dear Friends of ARCHIMEDES and the Mars Society,

MIRIAM was launched to a 175km peak altitude from the SSC ESRANGE rocket test site near Kiruna, North Sweden on October 22nd, 2008. It rode on top of the REXUS4 sounding rocket managed and built by the EoruLaunch Consortium of the DLR Moraba group of Oberpfaffenhofen, Germany and ESA.

Unfortunately, after a trouble-free testing period leading up to a picture perfect launch, one of MIRIAM's main interlock bolts jammed upon release. Miriam therefore got stuck on the rocket, which subsequently led to the balloon's clamp ring to get stuck as well.
With the stuck clamp ring, the inflation systems deck started to pressurize a still packed balloon, until overpressure pushed the inflation hose off the hose clamp assembly.

The flight system finally released from the rocket, but far too late. And with the deployment coil springs almost fully extended, it also came off far too slowly, eventually colliding with the rocket's payload section.
Unintentionally positive however, the collision caused the stuck clamp ring to come off, causing a rapid deployment of our partly pressurized balloon.
Because the balloon is only attached to the inflation systems deck at the inflation hose clamp assembly, the balloon was immediately set free, but with little over 10% of its intended amount of filling gas.

All other subsystems functioned nominally and behaved just like they did during tests.

Despite the fact that the balloon was deployed and released, the mission was deemed only partly successful, as the deployment came unintentionally and uncontrolled, and because the balloon did not carry its intended amount of inflation gas.

The reason why one of the main interlocks failed is a matter of investigation. This behavior was never observed during tests.

All subsystems of the REXUS-4 rocket have worked beautifully, exactly as predicted and right on time. We therefore owe EuroLaunch as well as the entire crew on ESRANGE great thanks for a beautiful flight, their outstanding technical support and a rocket as precise as clockwork.

While at it, we would like to take the opportunity to thank everyone who contributed to this mission, no matter how small the contribution was, since every contribution helped us getting off the pad!

After the collision knocked off the stuck clamp ring, the partly pressurized balloon deployed rapidly approximately 140km over beautiful Lappland.

Like in a wide-angle passenger side mirror, "objects in a wide angle camera are closer than they appear": The rocket's payload section as seen from MIRIAM. Unfortunately, the distance here is less than 2m. The balloon's diameter is 4m.

Shortly after atmospheric reentry, the camera- and antenna booms were torn off the discarded MIRIAM Service Module by aerodynamic forces, as they were not designed to withstand reentry. Miraculously, a short while into reentry, the right camera boom came on-line again and briefly transmitted pictures as it was dangling on its wire harness. Sunlight can be seen shining through gaps between the now empty balloon compartment and the obviously still working flight computer module. The coil spring is a remnant of the long gone blossom container inside which the folded balloon rode into space.

Thursday, October 23, 2008

Day 7: Last Day at Esrange


I am posting yesterday's and today's posts back-to-back, so you may now read the happenings of the launch day below. Today, the day after the launch, moods have improved quite a bit, given that we are getting more and more useful data and can reconstruct more of the mission sequence. Despite the ambiguity and potential damage caused by the collision, most of our systems behaved nominally. Today was a welcome contrast to the stress leading up to the launch, while discussion of our results continued spontaneously throughout the day. A few of us hiked down to the river straddling Esrange. Later at night, a dinner party was held with all the teams, followed by more review of our videos. Let me just say that the people from the Swedish Space Corporation have been extremely hospitable to us and made the stay here a pleasure for all (and always with a great sense of humor).

I will leave Esrange tomorrow morning to return to the U.S. Some of the team will stay behind for a few more days to further evaluate the data. We have learned an incredible amount as a team and individually, from flight operations, team work, procedures, engineering, testing and much more abstract things which can't be summed up in text. The data we gathered will no doubt benefit our knowledge and understanding of such a complex system and guide us to and during future projects. Experimentation and experience go hand-in-hand. We also just had plain fun doing this, and I will certainly miss Esrange and everyone on the team. Of course, the project is far from dead, and therefore most of us are nearly guaranteed to stay in contact and probably cross paths again. I will continue this blog as more information about the flight becomes available. For now, enjoy the pictures of my last day at Esrange below.

River just beyond the Esrange fence.

Spent rocket stages are turned into a modern art-like mess of twisted metal.

Striking the "Dr. Strangelove" pose on a spent Nike booster. These are derived from now obsolete anti-aircraft missiles, some of which did indeed carry nuclear warheads during the Cold War.

The "Highway to the Danger Zone"

Good Bye, Esrange

Day 6: Launch and Mission Summary


Sorry this post comes a day late, but the mission sequence necessitated us to stay silent for a while to avoid speculative misinformation and to be sure we know exactly what results we could draw from the mission. Indeed, we are still learning about the flight and probably will be for quite some time into the future. After a much accelerated count-down, Rexus 4 did finally launch and I have attached the video below. I apologize for the marginal quality, as I took this on my small photo-camera. We have slightly better launch videos, but for now this was the most suited to put on the web.


Now, to the mission itself. We still don't know the extend of success of the mission, pending further evaluation of our data. There was, however, a compromising event which affected the mission to some extend. After what began as a picture-perfect launch, MIRIAM began to transmit breathtaking views from space. All cameras worked flawlessly and recorded separation of the service module. However, a short time after MIRIAM separation, the payload section (containing our Camera Module on top and other experiments below) underneath the service module separated from the second stage booster as planned, but then collided with the Service Module. The impact happened approximately 15 seconds after the balloon was ejected and during the inflation sequence. A partially inflated balloon can be see just before impact, validating at least part of the experiment. The collision induced some tumbling and the fate of the balloon and instrument pod are yet uncertain, pending further evaluation of the video material, telemetry data and possibly recovery of either service module or instrument pod (the camera module is already recovered with the rest of the payload section). The service module continued to perform the inflation sequence nominally and continued to relay data until re-entering the atmosphere, offering stunning views of northern Scandinavia.

After hours of watching the tapes, this is the best account we can give so far. What seemed at first like a shocking deja-vu of the previous REGINA mission, turned out to be most likely caused by a distinct issue. As was quickly determined, both our timers and the rocket's timers behaved normally and issued separation signals on time. In contrast to Regina, the added first stage and much higher trajectory should have given us adequate time to distance ourselves from the payload section and booster. This, however, was not the case due to the service module becoming stuck on one of three of servomotors forming the locking mechanism. These servos were tested extensively on the shaker table, but the exact failure mode still needs to be determined. Although all servos opened at least partially, causing the separation signal to appear, MIRIAM did not become lose for another approximately 21 seconds. Even then, it no longer had an appreciable separation impulse, as the separation springs had already triggered. This caused it to drift slowly and delayed from the payload section below, resulting in inadequate separation distance and allowing the following payload section to catch up and collide.

Nevertheless, much useful data could be obtained, and the fate of the balloon is yet to be determined. Despite an unforeseen mechanical failure of the servo, many processes and systems performed beautifully, validating many aspects of our experiment.

Please note that this account is preliminary and unofficial, and as such can only be confirmed by the official press release.

Tuesday, October 21, 2008

Day 5: The Anticipation Rises....


Sorry, no pictures today, as the anticipation and stress for all of us has been rising. Hopefully though, the next pictures you will see here will be of a rocket streaking to the sky. During the MORABA/SSC briefing today, we were informed of the critical situation regarding the launch prospects. Due to some glitches on the side of the launch providers, such as a "non-conforming fin," and weather, the schedule has been pushed and squeezed. The two rocket stages were mated and the stabilizing fin was fixed, but one had to ensure it had been fixed "to specifications." As the ever-calm SSC campaign director put it, "it is easier to bend steel than paper." What's more, this also meant the practice count-down had to be postponed, while at the same time, we only have a very small launch window on Wednesday due to wind. Weather is expected to only deteriorate thereafter. Should we not launch this week, launch may still be possible, but with a greatly reduced team (as most will already have left Esrange) and increased work-load. The decision was reached to postpone the practice count-down to Wednesday, at 5am, at a potentially accelerated pace in order to resume the "hot" count down not much later that day. This is thought to give the greatest chance to launch within the unbendable safety regulations.

This meant that the rocket was fully assembled tonight, while MIRIAM was partially pressurized with Helium and secured at the top of the rocket. The rest of the pressurization will happen tomorrow, most likely between practice and real count downs (necessitating special security passes for the team members handling MIRIAM on the launch pad). MIRIAM needs to be pressurized in two stages, as the gas under pressure is heated, and thus expands, and needs to be allowed time to cool down before "toping it off."

Luciana and I also held our trajectory briefing later in the evening, after the launch-prep team had secured MIRIAM on the rocket. After programming and ironing out our trajectory visualizations and calculations for most of the day, I think the briefing gave everyone a good idea of the series of events and flight paths of the MIRIAM components during the mission. Now, all we can do is hope it all goes as planned, and the very first purpose-designed inflatable atmospheric entry vehicle will be deployed in space tomorrow.

Crossing fingers,


Monday, October 20, 2008

Day 4: Safety briefing and Trajectory Simulation


There won't be a long update today, since I had to attend briefings and work on our trajectory simulation for most of the day instead of shadowing people and taking pictures. We were joined by four more visitors of the German Mars Society and had a project-internal morning meeting to discuss our go-ahead plan and status. Everything seems to be going well. In the afternoon, the site operators held a joint briefing regarding launch prospects and safety. It looks like, while the winds won't be perfect, we are still scheduled to launch on Wednesday morning. One potential issue surfaced involving a missed opportunity to do an RF-interference test between us and another experiment on board, which will have to happen tomorrow morning. Other scenarios such as contingency planning for launch aborts etc., and their effect on our battery life, were discussed. The safety briefing was necessarily serious, as expected from any undertaking involving high explosives and accidents have happened. Our use of cellphones and controlling potential sources of static discharges are highly monitored, as well as access to the restricted areas during countdown.

As far as the trajectory simulation goes, Luciana and I are preparing a general trajectory briefing for our team tomorrow. Our actual trajectory is determined by the Rexus 4 operators, but since we have the service module and re-entry vehicle which detach from the rocket, a rough idea of the flight paths is desired. We are using the same program developed by the University of the Federal Armed Forces, which I adapted for use with MIRIAM during my summer internship. Since MIRIAM is a technology demonstrator for a Mars mission, we do not expect the re-entry ballute to survive re-entry on Earth, and much depends on when exactly the balloon will burst.

Lastly, I will share some pictures, courtesy of Jürgen.

MIRIAM arrived with the nose cone of the rocket. It took some convincing of customs officials to determine the legality of the shipment.

The Nike and Improved Orion solid propellant stages of our carrier rocket.

Members of the MIRIAM Team and German Mars Society briefing in the morning.