The Plan 8 from Outer Space Video

I created this short video for my new robot, Plan 8 from Outer Space. I recently added a robotic arm to the robot and ended the arm with a red photometer. It's now a good model of a planetary rover.

Plan 8 From Outer Space

I've nearly completed my latest robotics project, a radio instructed robot, or rover. The robot does not respond to joystick commands like a game. Instead, Plan 8 from Outer Space receives text instructions from a radio terminal. The commands are parsed and then acted on as long as they are valid. Except for it's robotic arm, the rover is complete.

Here's a list of the commands the rover can act on.
1. Move forwards or backwards
2. Move sideways left or right
3. Move diagonally, forwards or backwards and left or right
4. Pivot in place
5. Turn clockwise or counterclockwise while moving forward or backward
6. Collect photometer data now or over time
7. Pivot a camera left or right within a 90 deg arc
8. Turn on its two laser (indicates the width of robot in video images)
9. Give range data to objects (five angles within 45 deg left and right)
10. Report body tilt

Eventually Plan 8 from Outer Space will be outfitted with an arm to measure the level of radioactivity within a sample.

The robot has an articulated body that twists as it drives over obstacles. The four wheels are driven and are independently steered. Several new NearSys kits are incorporated into the robot, so look for these soon.

1. Smart Sonar (scanning sonar)
2. Accelerometer (used to measure tilt of the robot body)
3. CheapBot-20 robot controller (based on the PICAXE-20) which steers four independent wheels, drives two banks of motors, and has eight I/O ports
4. Bi-directional radio terminal

A side view of my new rover

A front view of my new rover

Thermal Vacuum Chamber

I finally have a thermal vacuum chmaber (TVC) design I like. It's called Near Space in a Can and it will sell for $250 as a kit plus shipping (minus the vacuum pump since it's cheaper to pick that up at the store than sell it).

The TVC has a diameter and depth of nine inches. It's exterior is packed with dry ice and it's then pumped down. Inside the environment approaches near space conditions. I'll add radioactive materials and evnetually UV sources to more faithfully replicate near space.

As long as you're willing to pay postage, I will expose experiments (not living objects, please) to the chamber at no other cost. Eventually I'd like to have several of these available for amateur testing.

NearSys 11N

Hard to believe, but I flew my 99th near space mission this weekend as NearSys 11N. I traveled to Valley, Nebraska to launch a ballon in conjunction with friend, Mark Conner. Mark and I go back to 1998 when we met at the St. Joe Hamfest in Missouri.

We ran into a small problem on this flight that ended up creating a bigger headache before it was all over. The helium tank we received was not properly topped off (about 20% low). As a result of the unexpectedly lower volume of helium, we were forced to remove some payloads. The reduction in payload weight also meant the parachute would descend slower, permitting a longer recovery.

To make a long story short, recovery should have occured in farm fields south of Anita, Iowa. Instead, recovery occurred in a small patch of woods near Adair. As is typical, the near spacecraft recovered on the very top of the trees. It took about an hour for Mark and me to retrieve the payload.

You can view the flight data on my website at, http://nearsys.com/arhab/flightdata/2011/n/index.htm.

Mark posted pictures at, https://picasaweb.google.com/111334632256807627139/NearSysFlight12Nov2011

Onwards and Upwards

Flight Number 99

Hard to believe, but I flew my 99th near space mission this weekend as NearSys 11N. I traveled to Valley, Nebraska to launch a ballon in conjunction with friend, Mark Conner. Mark and I go back to 1998 when we met at the St. Joe Hamfest in Missouri.

We ran into a small problem on this flight that ended up creating a bigger headache before it was all over. The helium tank we received was not properly topped off (about 20% low). As a result of the unexpectedly lower volume of helium, we were forced to remove some payloads. The reduction in payload weight also meant the parachute would descend slower, permitting a longer recovery.

To make a long story short, recovery should have occured in farm fields south of Anita, Iowa. Instead, recovery occurred in a small patch of woods near Adair. As is typical, the near spacecraft recovered on the very top of the trees. It took about an hour for Mark and me to retrieve the payload.

You can view the flight data on my website at, http://nearsys.com/arhab/flightdata/2011/n/index.htm.

Mark posted pictures at, https://picasaweb.google.com/111334632256807627139/NearSysFlight12Nov2011

Onwards and Upwards

Introducing BalloonSats

An alternative to using robotics as a vehicle for teaching STEM is the BalloonSat project. One reason BalloonSats may make a superior alternative to robotics is that robotics doesn’t involve as much science and mathematics as a well structured BalloonSat project. And while robots in competition can operate in either autonomously (independent of a human operator) or with operator control (by human control, usually over a radio), BalloonSats can only operate in autonomous mode. Students design and program their BalloonSat to operate sensors and collect data without human intervention.

Description of a BalloonSat

BalloonSats, as Linda Kehr describes them, are model satellites carried under helium filled weather balloons to altitudes in excess of 80,000 feet, a very space-like environment. In fact, BalloonSat flights reach 85,000 feet easily and can reach over 120,000 feet with lighter payloads and larger balloons.

BalloonSats are the first step in the National Space Grant Satellite Program’s strategy, “crawl, walk, fly, run”, whose ultimate goal is to send a student-designed payload to Mars. However, the first step, “crawl” is designed to encourage students to build and fly simple models of satellites, like BalloonSats. It is believed that by getting students involved in a series of more complex projects, more will graduate from STEM programs and enter into aerospace engineering fields.

Description of their construction

BalloonSats are an inexpensive way to access space while still retaining some of design and engineering challenges of satellites (Kohler 2003).

Airframe

BalloonSats are student designed from Styrofoam to carry programmable dataloggers and cameras and typically do not weigh more one pound (Kennon, Roberts & Fuller 2008). Other design challenges may involve volume (not to exceed 1000 cc), minimum datalogging capability (internal and external temperatures over the entire flight) and functional testing preflight. Adhesives used to assemble the BalloonSat airframe from foamcore include silicon rubber glue, hot glue, and JB Weld (an epoxy). Aluminum duct tape is also a popular material to seal the airframe (Koehler 2003).

Figure 1. Example of a BalloonSat. This one is constructed from a sheet of ½” thick Styrofoam, the same material used as insulation of outside house walls. It’s walls are assembled with hot glue and covered in black packaging tape. Photograph from the author’s collection.

Avionics

The datalogger used when BalloonSats were first designed is the Hobo datalogger. Scouts involved with the Glenn Research Center’s BHALF (BalloonSat High Altitude Flight) are beginning to experiment with using BASIC Stamps by Parallax – the same microcontroller used in the Boe-bot robot (BHALF). For Students in CU Boulder’s Gateway to Space course who are ready for a more advanced challenge, the timer is replaced with a programmable BASIC Stamp.

After recovery of their BalloonSat, students connect the datalogger and camera to a PC to retrieve the data and images. Students can perform their own mathematical analysis of the data and images or rely on the software used to program the dataloggers.

Figure 2. An eight-bit Hobo datalogger manufactured by OnSet Computing. This model records internal temperature and an external voltage. Photograph from the author’s collection.

A one time popular camera for BalloonSats was the Canon Elph. These APS film cameras were relatively inexpensive and very easy to modify for operation by intervalometers. The intervalometer is a 555 IC based timer kit soldered together by students. More recently, digital cameras and digital video recorders are included in the BalloonSats.

Preflight testing

Prior to flight, their designers test their BalloonSats. Even though flights cost less than $300, this is still too expensive to launch a BalloonSat that has no guarantee of functioning properly. Typical tests used in Koehler’s program include the following.

Drop Test: BalloonSats land by parachute. At touchdown, the BalloonSat’s speed can easily reach 10 mph. To ensure BalloonSats will remain in one piece during the landing, students drop their BalloonSats from a height that simulates their landing of 10 mph. The height from which a BalloonSat must be dropped to simulate a 10 mph landing can be calculated as shown below.
10 mph * 5280 ft/mile * 1 hour/60 minutes * 1 minute/60 seconds = 32.2ft/s2 * t
time of fall = 0.455 seconds
h = ½ * 32.2 * (0.445)2
height of drop = 3.34 feet

Cooler Test: Near space gets very cold (the coldest temperature the author’s BalloonSats have measured is -90O F, although -60O F is more typical). To ensure the BalloonSat is build well enough to keep its datalogger contents warm enough to function is to place the BalloonSat inside a Styrofoam ice chest filled with dry ice. The BalloonSat is left inside the cooler long enough to let the interior temperature bottom out (the author uses a time of 20 to 30 minutes).

Functional Tests: During its construction and at the competition, the BalloonSat, its datalogger, intervalometer, and camera are tested together to verify they will work without interfering with each other. This means all subsystems must fit inside the airframe without blocking access to the camera power button or the camera’s view outside the airframe.

Description of launch/recovery

BalloonSats are lofted into near space on a helium-filled weather balloon. The entire vehicle consists of a helium-filled weather balloon at the top, a recovery parachute attached below the balloon by a load line of nylon cord, one or more GPS trackers packed inside a Styrofoam enclosure, and one or more BalloonSats (Koehler 2003). The GPS tracker transmits position reports of the balloon over amateur radio frequencies. The system amateur radio operators use to track the location of items (like automobiles) is called the Automatic Packet Reporting System, or APRS. Therefore, a licensed amateur radio operator is required on each near space launch. The expendable parts of the flight are the helium and latex weather balloon and accounts for the $300 price tag for the flight. The radio tracking equipment are repaired, if necessary, so it can track another mission.
Recently, Taylor University began marketing a license-free version (900 MHz spread-spectrum) of the radio tracker. The system is called the High Altitude Research Platform (HARP) and is marketed by StratoStar. To date, over 200 flights using the StratoStar system have taken place.

The maximum weight on most BalloonSat launches is 12 pounds as long as no single item weighs more than six pounds nor has a surface density greater than one ounce per square inch. Additional FAA rules apply when these limits are exceeded (Federal Aviation Administration, FAR 101). Therefore, to avoid the application of additional FAA procedures, most schools launching BalloonSat limit their flights to 12 pounds total weight.

The typical BalloonSat launch occurs in the morning and requires between two and three hours to complete. The early morning launch permits the balloon to be filled while the winds are generally lower. After release, the typical ascent rate for the weather balloon and payload is 1,000 feet per minute. Latex weather balloons are sold by weight and frequently used balloons are 1200 and 1500 grams. Kaymont is an example of weather balloon dealer located in the United States.

A balloon filling system consisting of a regulator designed for welding gases, oxygen hose, and a length of PVC pipe. The PVC pipe attaches to the end of the oxygen hose and has a diameter less than the diameter of the balloon’s nozzle. The balloon nozzle slides over the PVC pipe and taped securely. Once secured, the balloon is filled with helium. Welding companies are the suppliers of helium required to launch a weather balloon. The helium arrives in welding tanks and they can weigh as much as 120 pounds.

Figure 5. Balloon Filler. The green oxygen hose is 12 feet long and the PVC pipe is 1.25 inches outside diameter. Photograph from the author’s collection.

Figure 6. University of Kansas students filling two latex weather balloons in preparation for BalloonSat launches. Photograph from the authors collection.

A typical flight requires 90-100 minutes to climb to peak altitude and approximately 30 minutes to descend back to the ground on its parachute. Because of the amateur radio equipment onboard, the balloon is tracked and its landing site located. Because of APRS onboard the balloon, students can track the position of the balloon carrying their BalloonSat in real time (Koehler 2003).

Near Space

According to Aerostar, near space begins at an altitude of 50,000 feet. According to the United States Air Force, near space begins at 20 km (65,600) feet, or above class A airspace.

Figure 7. Example of air pressure measured as a function of altitude by a BalloonSat. Environmental sensors from this author’s past near space flights indicate the air pressure drops to 10 mb, or 99% of a vacuum at an altitude of 100,000 feet (Data from the author’s collection).

Figure 8. Example of air temperature measured as a function of altitude by a BalloonSat. Air temperature drops to a low of -60O F in the summer and lower in the winter at the boundary between the troposphere and the stratosphere (Data from the author’s collection).

Figure 9. Example of the relative humidity measured as a function of altitude by a BalloonSat (Data from the author’s collection).

Figure 10. Example of cosmic ray flux measured as a function of altitude by a BalloonSat. The flux of secondary cosmic rays increases as the altitude increases until well into the stratosphere, where primary cosmic rays begin to be detected (From author’s personal data).

Figure 11. Example of an image returned by a BalloonSat showing the blackness of space and the curvature of the earth. A digital camera modified for operation by a programmable flight computer recorded this image of near space at an altitude of 78,000 feet (Image from the author’s collection).

Infrared for Digital Cameras

I began an investigation into adapting the cameras in my dissertation BalloonSat kit for infrared use. If you've looked for IR filters recently, you'll find they get pretty expensive. In place of a traditional IR filter, I made one according to the directions of Bill Beatty. He recommended using several layers of Congo Blue lighting gels and one of Primary Red. The blue gels are so dense in color that they block most of the visible light trying to get through them, so only a little of the blue gets though. The red gel manages to block the small amount of blue that gets through.

Stage lighting gels must be transparent to IR or else they will get too hot and melt. So if they can be stacked to block visible light, then only IR is going to get through them.

Digital cameras are naturally sensitive to IR. In fact, they need IR blocking filters to keep the appearance of their images looking like we expect. Now the camera must adjust its exposure time to compensate for the purely IR image, but my dissertation camera can handle it. I'll have to look into the effects of increased exposure time and the unsteady tripod that a BalloonSat simulates. However, if this is not too much of an issue, I expect two cameras, one with IR filter and one without, to make a great near space experiment for students.

This is the visible image taken on Wednesday afternoon. Pretty normal looking.

This is the infrared image taken on Thursday afternoon. Notice how bright the tree leaves appear. Chlorophyll is very reflective in IR. Also note how much brighter the trees are than the apartments behind them in IR (but not visible).