The equipment used for near-space balloon launches will vary greatly across teams and missions. Some teams may opt to use less sophisticated tracking and communications systems to keep costs low, while others may decide to invest in more elaborate systems. UCSD has experience with both approaches, and is investigating low-cost balloon launch options which may be suitable for use by educators on a limited budget.
The onboard payloads carried by the balloon will vary from mission to mission, and the equipment associated with each payload will dictate the required support equipment the team must carry to the launch site. In addition, teams will likely need to transport more personnel support and safety equipment if they are launching from remote locations. Because UCSD launches from a remote desert location, the team always carries additional supplies to ensure a safe and functional ground station at the launch site. Therefore, the equipment listed here will be divided into two broad categories: balloon-specific equipment, and ground support equipment.
Balloon-Specific Equipment: (TOP)
Communications and Tracking:
StratoStar System: UCSD uses StratoStar's StratoSAT kit for communication with the balloon. This kit was designed specifically for near-space ballooning. There are several StratoStar components on the balloon: the command module, cutdown mechanism, backup tracking module, and Zigbee wireless communication devices.
The command module is a sealed cylindrical unit which uses a GPS receiver to determine location and transmits position data using a 900 MHz antenna. In addition, the command module gathers and transmits atmospheric data and data from the payload pods if Zigbees are being used. Zigbees are small wireless devices that can be placed in each payload pod to establish a local 2.4GHz wireless network between the pods and command module. The command module also transmits GPS data to a backup tracking module and a cutdown module.
The backup tracking module is another sealed cylindrical device, and is used to transmit position data on HAM radio frequencies using an APRS (Automatic Packet Reporting System) system. The GPS data is received from the command module over the local wireless network. This system provides a second tracking signal for the ground team to use in the event that the primary 900MHz tracking signal cannot be received.
If the team wants to limit the peak altitude of the balloon, they can use the cut down module to prevent the balloon from exceeding a pre-defined altitude. The pre-defined altitude can be programmed into the cutdown module prior to launch, and the module receives current altitude data from the command module during the flight. If used, the cutdown module is placed between the balloon and the parachute. It has a mechanical clamp which securely holds the balloon during the mission, and then releases the balloon if the pre-defined altitude limit is reached.
SPOT GPS messenger: The SPOT GPS messenger is a small hand held device designed for use by hikers and other outdoor adventurers. The SPOT receives GPS signals, and transmits position data to the 'findmespot' website using satellite communication. The 'track progress' feature is particularly useful to UCSD: when this feature is activated, the SPOT receives GPS position data and uploads that data to the website every ten minutes. The current position can then be displayed using Google maps, along with recent position data. Since the SPOT uses satellite communication, it is not limited to areas with cell phone coverage. Because UCSD launches in the desert, this feature is particularly valuable: cell phone coverage is often spotty or non-existent in the landing zone. Our team flies a SPOT on every balloon, providing extra confidence that we will find the payload on the ground. In addition, the SPOT can be helpful in the unfortunate event of payload separation: attaching a SPOT to the bottom-most payload pod provides a chance at locating lost payloads. (This assumes that another functional tracking system is attached to the upper-most payload boxes.)
The SPOT Messengers used by UCSD have proven to be extremely rugged, and have remained operational throughout their flights even after direct exposure to the extreme near-space environment. However, it should be noted that the SPOT is designed to provide position reports near the ground, and will not provide position reports at higher altitudes (approximately 21000 feet and up.) This makes the SPOT an excellent tool for recovery of payloads after landing, but limits it's ability to track the balloon during flight. Any individuals considering the SPOT for a near-space launch are encouraged to keep this in mind when designing their tracking and recovery systems. In addition, the SPOT should be placed on the payload in such a way that the face of the device has a clear view of the sky upon landing.
Typical balloon setup
Balloon: UCSD uses standard KCL 1500 balloons from Kaymont. Technically called sounding balloons, these are what research scientists and near space enthusiasts across the US use. The KCL is the weight of the balloon in grams. The larger the balloon, the larger the KCL. Larger balloons can hold more helium, and therefore can be used to lift more weight. The Kaymont website can be found here.
Parachute: A parachute is needed to slow the descent from near space to the ground. Parachutes come in all shapes and sizes and can be readily purchased in hobby stores or can be made by hand. Make sure that the parachute you use is designed for the total weight of your payload.
The balloons we launch have the parachutes connected as seen above, with the parachute between the balloon and the payloads & command modules. Alternative configurations are possible, including having a second line from your top payload box to your parachute. Either way it is important to note the shroud ring, a hoop which spreads out the parachute lines and helps it open up on descent. Wooden embroidery hoops tend to work very well.
Many parachutes come in bright, easy to see colors. This is so that the parachute can be easily found when surrounded by underbrush and shrubbery for miles around. GPS points are only approximations to location, and even with the best of information having a parachute which stands out rather than blends in makes the search mission much easier.
Lines and payload harness: Nylon and other lightweight strong rope works very well. You want something strong which will not fray, will hold at very low temperatures, and is easy to work with. In addition, many ropes come in bright colors which, like the parachute, will provide a color contrast against the natural background when you are looking for your balloon.
A good way to ensure that the box will be there when you go to pick it up is to encase it in a harness of abrasion jacket. These "sleeves" tie right into the lines and prevent the boxes from slipping away. More elaborate schemes can be built, for instance modular sleeves for multiple, smaller boxes per harness.
Payload boxes: These must be lightweight, crash resistant, and possibly insulated. Always plan for the case in which the parachute does not work and the payloads drop at 60 miles per hour. The more crash resistant they are, the better chance you have of getting your equipment back. Styrofoam is a good material because it is light, works as a good crash barrier, and is easily shaped. Tools such as hot wire cutters melt right through it, preventing the fuzzy static flakes caused by cutting. It is important to note that most aerosols dissolve Styrofoam, so avoid them.
Environmental Control: (TOP)
Kapton Tape: This tape keeps going where duct tape wears out. Near space is too cold for duct tape, and other tapes, to continue to hold. Kapton works from -273 to 400 C, meaning it will work at pretty much any temperature. It has a high resistance to radiation damage, and we wrap it around anything we want to protect from space radiation.
Chemical Heat Packs: These small packets were originally designed for keeping gloved hands warm during winter sports. However, they work great for providing heat to payload box experiments. The hand heaters used by UCSD do not require the presence of air to sustain their exothermic chemical reactions, making them ideal for near-space balloon launches. These heater packets are reusable, and reach 130 degrees Fahrenheit within 15 seconds.
Chemical heat packs
Ground Support Equipment:
Communications and Tracking: (TOP)
Ground station laptops with StratoStar Software and antennae: Laptop computers are used to track the balloon after it has been launched. Two computers are used at the ground station, in case one computer fails during the mission. These computers are connected to a long-range directional antenna (obtained from StratoStar) which receives signals from the balloon during flight. StratoStar software is installed on each computer, along with Microsoft Maps. The StratoStar software permits the computers to decode the signals from the antenna, and plot the balloon position using Microsoft Maps. The tracking antenna is affixed to a tripod, and must be manually adjusted for the best line of sight. These computers serve as the primary tracking station: data obtained from this station is relayed to the chase vehicles via cell phone or hand held radio.
Chase vehicle laptops with StratoStar Software and antennae: A laptop with StratoStar software and Microsoft Maps is carried in one of the chase vehicles. This laptop is connected to a small omni-directional antenna which is magnetically affixed to the roof of the vehicle. Using Microsoft Maps, the chase team can view the balloon position. This is used as a secondary tracking system, and requires the chase vehicle to be in the vicinity of the balloon. The chase team relies on the ground station personnel to provide balloon position data in the event that the vehicle's tracking system is unable to receive a signal from the balloon.
VX-8R HAM radio transceiver with APRS: If the balloon's primary tracking signal cannot be received by either the ground station or the chase team, then a hand held HAM radio can be used to receive the backup APRS tracking signal from the balloon. This system can be used in areas where cell phone coverage may be weak or absent, prohibiting smart phones from accessing the APRS website.
Smart phones: Cell phones of any kind are useful for communication between team members, but smart phones equipped with GPS and websurfing features are exceptionally useful. If the primary signal from the balloon cannot be received by either the ground station or the chase team, then the team relies upon the balloon's backup HAM radio signal. The APRS data from the backup system is received by any HAM stations in the area, and uploaded to a website which interfaces with Google maps. This website can be accessed using smart phones to view the balloon's position if cell phone coverage is adequate.
Hand-held radios: In case cell phone signals are unreliable in the launch and recovery zones, UCSD uses common handheld radios to keep the ground station and chase vehicles in contact with each other.
Balloon Preparation / Filling: (TOP)
Helium tanks and regulators: The balloon must be filled with Helium on-site, immediately prior to launch. Two Helium tanks containing 217 cubic feet of Helium are transported to the launch site, along with the hoses and regulators required to safely release the Helium gas from the tanks during fill.
Two team members filling the balloon
Balloon ties: The balloon is sealed after fill using several zip-ties. The zip-ties used contain metal teeth, as opposed to standard plastic zip ties. This is because plastic zip ties can become brittle and fail in the extreme cold of near-space.
Protective Tarps: Protective tarps are carried to the launch site to provide a clean surface for filling the balloon and preparing the payload boxes. This helps to protect the equipment from the desert dust.
Ground Station: (TOP)
Generator and extension cords: A generator is carried to launch site to provide power for the ground station laptops and other equipment. Plenty of extension cords and power strips are also carried to the site. The generator is set in a location that is not directly next to the launch activities, in order to prevent the exhaust and noise from disturbing the team.
Tents, tables, and chairs: Tents are set up at the launch site to provide protection from the sun for the ground station team and also to make it easier to read the laptop screens. A folding table is carried to provide a location for the laptops, and folding chairs are also transported to the site.
Extra water: The team always carries plenty of water to the launch site, and in the chase vehicles.
First Aid Kit / hygiene supplies: Because the launch occurs in a remote location, a first aid kit must be available in case of injury. The team always checks the location of the nearest medical center in case of serious emergencies. In addition, restroom facilities are often not available. Planning ahead generally prevents this from being a problem, but toilet paper and hand sanitation gel is carried in case waiting is not an option.
Maps: The team uses mapping software primarily, but paper maps are also carried in case of equipment failure.
Transportation / Chase team:
Chase vehicles: The vehicles used to transport the equipment and team to the launch site are also used to follow the balloon during flight, and to recover the balloon when it has landed. Generally two vehicles are used for this purpose, and these must be capable of some off-road driving. Often the balloon will land in a remote location which can only be reached by driving on poorly maintained dirt roads, and the chase vehicle must be able to carry the team as close to the balloon as possible to minimize hiking through the desert.
Tie-downs: Tie-downs are critical for holding the Helium tanks during the drive to the launch site and prevent them from being damaged. These are also important for securing other large pieces of equipment, such as the generator and tables.
Jack and air pump: The chase vehicles may have to drive in rough terrain, so the equipment necessary to change a flat tire and inflate tires must be carried.
First aid kit: A first aid kit is carried on the chase vehicle in case of minor injuries. In addition, the team always checks the location of the nearest medical center in case of significant injury.
Maps: The chase team carries paper maps of the region in case their primary mapping software fails. In addition, maps that show restricted area boundaries are carried. (There are military areas in the desert that UCSD generally uses for near-space balloon launches.)
Screwdrivers, wrenches, pliers: These general tools are carried to the launch site to aid in balloon preparation. (Some battery compartments must be accessed using a screwdriver.)
Scissors: Scissors are used to cut the kapton tape during payload box preparation and sealing. They are also kept on hand for general use.
Swiss army knife: These are compact enough to be carried by the chase team when hiking to recover the balloon, and can provide a handy pair of scissors if the balloon lines are tangled in any brush or fencing.