9 May 2007: Gadget Communications Improvements

Yesterday our Operations Manager made several modifications to our communications method with Gadget and achieved a dramatic improvement in the downlink rate. Over three passes, we downloaded nearly 400 kB of data, which put us at well over 1 MB of total data obtained from Gadget. On our last pass of the day, we downloaded a whopping 237.5 kB of data. While these data rates may be small compared to conventional large spacecraft, for a picosat about the size of a pint glass, they are pretty impressive. Additionally, our operations modifications succeeded in bringing Gadget's battery up to 100% charge level, which bodes well for long-duration operations. Gadget's GPS receiver is also getting tantalizingly close to acquiring a trajectory solution, but has not yet achieved a lock during the periods where we have downloaded data.

7 May 2007: Mission Update & Tether Deployment Status

Over the past week, we have continued to have excellent success in contacting Gadget and downloading data from it. So far we have acquired over 800 kB of data from Gadget, with as much as 115 kB downloaded in a single pass over the groundstation. Late Saturday night, Ralph was scheduled to awake from hibernation and turn on its radio. Ralph has only two small solar cells on one face of the satellite, so it is primarily operating on its battery power, and its lifetime was expected to be only about one day. Unfortunately, due to scheduling issues, our first opportunity to attempt contact with it was not until late Sunday night, and our groundstation did not receive any signals from Ralph. We believe that Ralph's battery charge level had already dropped below the level needed to sustain radio operation. As Ralph's purpose has always been to serve as a ballast mass for the tether, its silence does not have a siginficant impact on the mission performance.

Based upon the data we have, we have concluded that Ted did separate from Gadget and begin to deploy the tether. However, a problem with the restraint system prevented Ted from ejecting smoothly, and as a result Ted was pushed away with too little momentum to continue pulling the tether off of the deployer spool. As a result, the deployment halted almost immediately. Our analysis of the magnetometer data we have downloaded from Gadget reveals that the tethered system is rotating slowly, but the length of tether connecting the two bodies is very short. At this point, we believe there is not enough energy in the rotation to pull more tether off of the spool. This is certainly disappointing, as it means that obtaining data on tether survivability may not be possible, but nonetheless we are obtaining interesting data that will be useful in validating models of the behavior of tethered spacecraft. We do have a back-up capability for potentially deploying additional tether, by having Gadget crawl towards Ted, but at this point we do not plan to exercise that option due to the risks involved.

The problem with the restraint system was a known potential show-stopper, among several others. With our limited budget for the project, we had to chose between the options of redesigning and rebuilding the experiment hardware, and then not having sufficient funds to launch the experiment, or flying what we had and seeing if it would work. We chose the latter, because we prefer the approach of trying multiple low-cost experiments, rather than a single very expensive experiment. While these results highlight the risks of performing a single-string, class-D mission on an extremely constrained budget, the successful operation of the Gadget picosatellite, the most complex and capable picosatellite flown to date, demonstrates that useful science can be accomplished on the picosatellite scale.

We will be continuing to download data from Gadget to enable us to understand the dynamics of this tethered system (albeit with a very short tether). Gadget's GPS unit has acquired an almanac from the GPS satellites, and we are hopefull that it will soon be able to lock onto a trajectory solution. Such GPS data will also be very useful in understanding the system's dynamics.

30 April 2007: Mission Update & Tether Deployment Status

Gadget continues to perform very well. We have established good communications links with Gadget on all of the passes where we've had access to the dish, and the changes in Gadget's operations have succeeded in bringing its battery charge levels up considerably. The higher battery charge level has enabled Gadget to operate its radio transmitter at full power, which improves data downlink bandwidth, as well as to periodically turn on its GPS unit. We have been able to download a number of messages from the GPS unit. However, we have not yet received a GPS message where the unit has been able to lock onto the GPS spacecraft and develop a position solution. We believe that this is due to the fact that Gadget is rotating slowly, which prevents the GPS's antenna from receiving signals from any one GPS satellite for long enough to receive the amount of data needed to establish a solution.

We have been listening for Ted on each pass, but have not received any signals from it. At this point, we believe that even if Ted is still functional, it is unlikely that we will be able to establish contact with it because its battery levels will likely be too low to support radio operations.

However, based upon our preliminary analyses of the data that we have received from Gadget, we are confident that Ted has separated from Gadget and at least a short portion of the tether has deployed. The length of tether deployed is as yet uncertain, and we are continuing to analyze the data to resolve this uncertainty. Nonetheless, we have been able to show excellent correlation between the observed magnetometer data (which provides us information on the orientation and rotational behavior of Gadget) and the predictions of our TetherSim numerical model.

We'd like to thank the many people who have tried to obtain optical sightings of MAST, and express our gratitude to our awesome dish operators.

25 April 2007: More Gadget Housekeeping and a Request for Big Eyeballs

Over the last couple of days we have been working to fine-tune the operating mode of Gadget to bring its battery levels up to the point where it can begin turning on its GPS unit. We have successfully uploaded several key commands to accomplish this, and during tonight's pass we hope to determine if these changes have helped. As we have not been able to establish contact with Ted, the picosatellite responsible for deploying the tether, we will now be focusing on getting data from Gadget so that we can analyze it to determine if the tether has deployed.

If any of our readers out there have access to a good telescope setup, we'd love to hear if you can see anything. MAST can be found in the Space-Track database as object 31126. Viewing opportunities for your location can be predicted by registering at Heavens-Above.com and searching for object 31126 in their database. The most opportune times to view MAST will be passes over your location that occur just after dusk and just before dawn.

23 April 2007: First In-Situ Photo of a Tether In Space (albeit pre-deployment)

During last night's pass we were again able to establish excellent contact with Gadget. We did not make contact with Ted. But Gadget sent us back a test-photo of the tether taken soon after the PPOD deployer ejected MAST into orbit. The photo matches very closely the pre-launch test photos, so our camera and lens are surviving the space environment nicely. To give you a sense of scale, the tether braids are about 0.5 mm in diameter. Please note that this is a photo of the portion of tether running through Gadget, taken prior to deployment of the tether.

21 April 2007: Fine-tuning Gadget

Yesterday, during a noon-time high-azimuth pass over the groundstation, we were unable to contact Gadget. We had expected this to be a strong communications pass, so this had us quite concerned until we discovered that the orbit ephemeri we used to program the ground station were actually several days old due to some sort of minor glitch at the Space-Track website. During the night-time pass, using the latest TLE's [thanks to the folks at Cheyenne Mountain!], we successfully contacted Gadget, downloaded both data from early in the mission and real-time data. During today's mid-day pass we downloaded additional housekeeping data and uploaded new ephemeri to help Gadget know when to turn on its radio. Gadget is functioning quite well, although the battery levels are lower than we'd like. We will be adjusting its operations to help increase the battery charge level and enable it to activate its GPS unit. We are very encouraged by Gadget's performance so far. The ability of the low-power 2.4 GHz radio we have used to establish contact with the ground station was one of our biggest technical concerns about the mission, and so far it is working like a champ. Also, there have been no resets of Gadget's computer, which is a good sign that the power management systems are working well. We are hoping soon to download several test-pictures of the tether inside Gadget's darkroom enclosure taken early in the mission. These will be important to verify operation of our tether inspection system and evaluate the rate at which we can download images.

We are still working to establish contact with Ted, the tether-deployer picosatellite. As a result, we are uncertain when or if the tether will be deployed.

The smallest picosat, Ralph, is set up to remain dormant until later in the mission, so we have not yet attempted to make contact with it.

20 April 2007: Gadget Lives

Late last night our engineers were successful in making contact with the 'Gadget' picosatellite during two passes over the ground station. The communications system worked better than we had anticipated, and Gadget appears relatively healthy based upon the early data we downloaded.

Today we will be working to contact 'Ted', the tether deployer picosatellite.

17 April 2007: MAST REACHES ORBIT!

According to CalPoly, the launch team at Baikonor reports that our MAST picosatellites have been successfully delivered into orbit! Our congratulations to Kosmotras for Dnepr's successful return-to-flight, and our hearty thanks to CalPoly for all their work in putting the launch together.

We expect to begin attempting to contact the MAST picosatellites on Friday.

16 April 2007: Acknowledgements

We'd like to take advantage of this calm before the storm to acknowledge the contributions of the many people and organizations that have assisted us in preparing the MAST experiment for flight:

• First, the hard work and long hours put in here at TUI by Tyrel, Ian, Nestor, Jeff, Scott, Jack, Josh, and Scott R., designing, building, programming, and testing the MAST picosatellites and tether deployment systems.
• Prof. BJ Jaroux, Prof. Twiggs, Prof. Cutler, and all the students who assisted in the development of the picosatellites.
• NASA/MSFC's In-Space Propulsion office and the NASA STTR office for funding and guidance that helped us develop the technologies for this flight.
• Triton Systems, Inc. for treating our tether materials with their magic atomic-oxygen resistant coating.
• CalPoly's University CubeSat program, for all their Integration & Test and launch support.
• Prof. Kitts and students, for helping with ground operations.
• SRI, for providing us access to their ground station resources.
• DLR, for providing their GPS solution.

13 April 2007: MAST Experiment to be Featured in Story on NPR's Morning Edition

NPR has interviewed TUI's CEO, Dr. Hoyt, and Les Johnson of NASA/MSFC about TUI's upcoming MAST flight experiment. The interview is scheduled to be aired on Morning Edition on Monday the 16th.

EDIT: The text and audio of the NPR story on Morning Edition are archived here.

11 April 2007: Ephemeri Updates

Here are the current predicted ephemeri for the MAST system, as reported by CalPoly's CubeSat program:

1 xxxxxU xxxxxxxx 07107.29311609 .00000000 00000-0 00000-0 0 0000x
2 xxxxx 098.0870 182.3615 0084000 198.3918 339.9240 14.5160000000001x
Launch Time UTC 4/17/2007 06:46:35

Prior to separation of the picosatellites, we expect the ballistic coefficient B to be 0.011, and the drag term B* to be 8.6331e-4. After tether deployment these coefficients are expected to be approximately B=0.561 and B*=4.4029e-2.

29 March 2007: More Press

The MAST experiment made the front page of engadget with an article here. They even called us "scientist-types...[with] nerdy humor," which after much deliberation we've decided to take as a compliment.

However, for the record, the names for the three picosatellites ('Ted', 'Gadget', and 'Ralph') were coined by the Stanford students who participated in the development of the picosatellites, so we can't actually take credit/blame for the names.

28 March 2007: Launch Rescheduled for 17 April 2007

The launch of the Dnepr rocket carrying the MAST experiment has been rescheduled for 17 April 2007, reportedly due to a problem with the third stage of the launch vehicle. While we are disappointed that we have to wait yet again for the launch, we are glad that they discovered the problem before launch, rather than after! Based on our health check-ups on the MAST picosatellites after previous delays, we do not anticipate any significant issues with battery discharge during this three-week delay.

The New Scientist has published a great feature story on our MAST experiment here.

Thank you for checking in on our MAST project, and please come back in three weeks!

27 March 2007: Launch Delayed

We've been notified by CalPoly that the launch has been delayed. We'll post the new launch date & time when we hear it.

23 March 2007: Expected Tether Visibility

Once deployed on orbit, our MAST tether will likely be visible to the naked eye under the right conditions. The best time to look for the tether will be when it is passing overhead just after dusk or just before dawn, so that it is illuminated by the sun while your location is still dark. At right is a picture of the SEDS-2 tether taken with an image-enhancer. One observer described the SEDS tether as "like a jedi-sword moving across the sky." Now, the SEDS tether was 20 kilometers long, and our MAST tether is just a wee little 1 kilometer long, and it'll orbit about twice as high as SEDS, so it will not subtend as large an angle across the sky, but we expect that it will be discernable as more than just a speck of light. Under the right conditions, it should subtend about five hundreths of a degree (about 1/7th the size of the moon, or like a dime 43 feet away from you!).

To find out when the MAST tether will be passing over your location, we recommend Heavens-Above.com and n2yo.com. We'd welcome receiving copies of any photographs or video captures you might make. Notations on camera orientation and observation time would be especially helpful in aiding with processing of tether dynamics data.

22 March 2007: Expected Timelines

After launch, we expect to have to wait for 3 days before attempting to establish contact with our MAST picosatellites. This delay is due to a conflict at the satellite dish station we are using for the mission communications. After that 3-day wait, we hope to contact the satellites and check on the status of their battery charging subsystems and operation of their GPS Units.

7 days after launch, the Nanosatellite Release Mechanism will be activated to separate the picosatellites. A set of springs will then push the "TED" picosatellite, which contains the tether deployer, away from the other two satellites. This initial kick should give the satellites sufficient momentum to deploy the experiment's 1-kilometer long tether. During the roughly 10-minute long deployment, we hope to obtain GPS data from two of the spacecraft to provide information on the dynamics of tether deployment.

We will then wait for approximately one week to allow the tether dynamics to stabilize, and to allow us to collect further data on tether dynamics. After that point, we will activate the crawling mechanism on the middle picosatellite ("Gadget"), so that it can slowly translate along the tether and inspect it for micrometeorite and orbital debris damage.

Here is a photo of the PPOD deployers ready for integration onto the "Space Head Module". (Photo courtesy CalPoly)

19 March 2007: PPOD Integration

We have received word from CalPoly that the PPOD deployers containing our MAST experiment have been succesfully integrated onto the launch vehicle.

15 March 2007: MAST Launch Date

On 27 March 2007, our MAST Experiment is scheduled to be launched as a secondary payload on a Dnepr rocket. Approximately a week after launch, the picosatellites will separate and deploy a 1-kilometer long tether in orbit. It will then conduct experiments to evaluate the survivability of tethers in the space environment and measure the dynamics of tethered formations of satellites.

Please check back here for mission updates.