New Ground Station! And other updates.

There has been exciting progress made since our last update (and how time flies!). We have completed a spacecraft flatsat earlier this year, demonstrating all spacecraft functionality in the clean room here on campus. We have also built a new ground station to communicate with our spacecraft. Additionally, we have made our submission for the fourth and final Ground Tournament that will determine our eligibility for the EM-1 launch! Finally, we have completed our Phase II safety review and are working on closing out action items given to us by the safety review panel.

New Ground Station

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Cislunar Explorers new ground station. Cornell’s clock tower can be seen in the lower right.

We have completed our upgraded ground station, which is on the top of Rhodes Hall, one of the highest points on campus. With this ground station, we can maintain a comfortable link margin with our spacecraft even at its farthest distance–over 1.2 million kilometers from Earth! The new ground station will support several flight projects in between now and the EM-1 launch that will hopefully fly Cislunar Explorers. This will give us ample opportunity to practice tracking and communicating with spacecraft in advance of our mission. Our old ground station remains on top of Barton Hall for use as a backup; its gain is sufficient to maintain communications with the spacecraft at the lunar distance where most of the mission will take place.

Ground Tournament 4

We have submitted our documentation for Ground Tournament 4, which is the final phase of the ground segment of the CubeQuest challenge. As one of five teams left in the competition, we are competing for three open launch spots on EM-1. The results will be announced the week of June 8th at NASA AMES.

Phase II Safety Review

We have also submitted our data package and completed our Phase II Safety Review presentation. While the Ground Tournaments determine which missions are chosen for launch opportunities, eligible teams must also pass a series of safety reviews from Phase 0 through Phase III, in order to be cleared to actually fly. We completed Phase 0 in 2015 and Phase I in 2016, closing all action items from both. The Phase II review has been conducted, and we are expecting to close related action items early this summer. At that point, if we are selected from GT4, we will only need to complete the final, Phase III review to launch!

Ground Tournament 3 Prize!

NASA’s Centennial Challenges program recently announced the results of the third Ground Tournament in the CubeQuest. The Cislunar Explorers team is proud to say that we won second place, earning a $30,000 prize! This brings us closer to our goal of being selected for launch on the EM-1 mission as a secondary payload, which will allow us to compete in the Lunar Derby and become among the first CubeSats to depart Earth orbit. It is a great followup to our prize-winning finish in the first Ground Tournament last year. The next and final Ground Tournament will be in February 2017. We hope to maintain our strong position to win another prize as well as an EM-1 launch opportunity!

We have been fortunate to earn a total of $80,000 so far due to our strong performance in both Ground Tournaments. Now, our fabrication and testing process is ramping up as we prepare to produce complete, space-ready CubeSats for Ground Tournament 4. We are off to a running start in  the build process, with our avionics, electrical power system, and engineering-unit spacecraft bus already completed. Funds raised in the crowd-funding effort on Kickstarter will defray these costs and reduce mission risk: we’ll be able to afford high-efficiency solar cells, 3D printed titanium combustion chambers, and more!


With your help, we can make the road to space an easier path for everyone!

NSS/Cislunar Explorers Press Release

(Washington, DC – September 26, 2016)

The National Space Society has teamed with Cornell University on the Cislunar Explorers CubeSat project. If this shoebox-size spacecraft successfully orbits the moon, it will be the first to demonstrate that water can propel a spacecraft. And this small step will be a giant leap toward democratizing access to space. That’s because the plans for every aspect of the spacecraft’s software and hardware will be available online. With an inexpensive and freely accessible design, this project will provide a means for virtually anyone to build an interplanetary spacecraft of their own.

“We now understand that water is abundant throughout the solar system, and in a few years water may become the single most versatile resource for a future of sustainable space exploration,” said Kyle Doyle, Cislunar Explorers Project Manager and Ph.D. student at Cornell University in Ithaca, NY. “It’s safe and inexpensive, and can be used to refuel a spacecraft like ours throughout its lifetime.  So, we expect this propulsion technology to broaden public participation in deep-space exploration.”

The Cislunar Explorers design consists of a pair of water-powered CubeSats entered into the NASA CubeQuest Challenge. This Challenge offers a total of $5 million to teams “delivering flight-qualified, small satellites capable of advanced operations near and beyond the moon.” Teams are judged by increasingly rigorous standards at a series of four “Ground Tournaments” as to the viability and maturity of their design. Cislunar Explorers has finished in the top three at both completed Ground Tournaments, including first place at Ground Tournament 2. The top three teams at the end will ride on NASA’s Space Launch System in 2018. If selected, the Cislunar Explorers will join twelve other CubeSats as secondary payloads: a fleet of nanosatellites demonstrating novel technologies in deep space.

The mission consists of two spacecraft launched together. Each contains a propellant tank full of liquid water. After launch, the two spacecraft push apart from each other thanks to a spring-loaded mechanism, which also causes each to spin. Solar panels provide electricity to separate water into highly combustible hydrogen and oxygen gas, the same rocket propellant used in the Space Shuttle main engine. In this way, the Cislunar Explorers are able to achieve lunar orbit using nothing more than water.


The Cislunar Explorers team has created a crowd-funding page on Kickstarter. Funds raised will support the purchase of flight hardware including high-efficiency solar cells and 3D printed titanium combustion chambers, as well as additional testing campaigns to reduce mission risk. The final design will be open source, with software, schematics, and test results made publicly available.

“We at the NSS are partnering with Cornell on this project because of the broad impact on space exploration and public engagement that it promises.” said Dean Larson, the Cislunar Explorers lead at NSS. “Successful crowd funding will help the team achieve our goal of reducing the barriers to sustained space explorations, making the solar system accessible to everyone.”

Kickstarter Launched!

We are happy to announce that our crowd-funding effort on Kickstarter has gone live! We have been fortunate to earn a total of $50,000 so far due to our strong performance in both Ground Tournaments. Now, our fabrication and testing process is ramping up as we prepare to produce complete, space-ready CubeSats for Ground Tournament 4. We are off to a running start in  the build process, with our avionics, electrical power system, and engineering-unit spacecraft bus already completed. Funds raised in the crowd-funding effort will defray these costs and reduce mission risk: we’ll be able to afford high-efficiency solar cells, 3D printed titanium combustion chambers, and more!

Our shiny new spacecraft bus (latest version just arrived 9/15)!

Our shiny new spacecraft bus (latest version just arrived 9/15)!


Ground Tournament 3 submission complete!

The Cislunar Explorers team is one of the competitors in the CubeQuest Challenge, a NASA Centennial Challenges program. We are seeking one of three launch manifests available through the CubeQuest, spots on the NASA Space Launch System (SLS) Exploration Mission 1 (EM-1). The primary payload for that launch is NASA’s Orion Multi-Purpose Crew Vehicle. If selected, the Cislunar Explorers will join a total of twelve other CubeSats as secondary payloads. We’ll be part of a fleet of nanosatellites demonstrating novel technologies in cislunar and deep space.

We have been very successful in the CubeQuest so far, winning prizes to help fund our continued development at both of the two “Ground Tournaments” so far. Last night, we completed and turned in our Ground Tournament 3 submission to NASA. This is the penultimate design review for the CubeQuest, meant to show NASA that we have a complete and thoroughly tested design ready for fabrication of flight units. Our submission contained close to 600 pages of documentation: images of test and prototype hardware, analysis and test results, details of our planned mission, schedules for future development, and documentation of safety compliance.

We’re excited to advance another chapter in the Challenge, and to continue our quest to launch on EM-1. Thanks for joining us in this effort! With your help, the Moon seems closer every day.

National Space Society

The Cislunar Explorers team is pleased to announce our collaboration with the National Space Society!

The National Space Society (NSS) is an independent, educational, grassroots, non-profit organization dedicated to the creation of a spacefaring civilization.  Founded as the National Space Institute (1974) and L5 Society (1975), which merged to form NSS in 1987 (see merger proclamation), NSS is widely acknowledged as the preeminent citizen’s voice on space.  NSS has over 50 chapters in the United States and around the world.  The society also publishes Ad Astra magazine, an award-winning periodical chronicling the most important developments in space.

We have been working closely with NSS Project Committee Chairman, Dr. Dean Larson, to align our goals with theirs. As part of our efforts, we are working with the NSS to find volunteers to assist with several tasks. You can find more information about what we are searching for on the NSS Cislunar Explorers project page.

The NSS publishes a wonderfully informative magazine, Ad Astra, which will include an article about our spacecraft in its next issue. At around that time, we will be launching our crowd-funding effort, and links to the donation page will be available here as well as on the NSS website. In exchange for NSS helping spread the word of our crowd funding efforts, we will be donating a portion of any CubeQuest space prize winnings to the organization.

Optical Navigation Thought Experiment

You can imagine yourself floating, with your eyes closed, somewhere in the general neighborhood of the Earth, Sun, and Moon. You have no idea which way you’re facing, and no idea where you are.

You open your eyes, and move your head around to look all around yourself. You’re wearing sunglasses (the Sun is awfully bright in space), so the only things that you can see are the disks of the Earth, the Sun, and the Moon. You can’t see any of the features on any of those celestial bodies (you can’t tell, for instance, if you’re looking at North America or Indonesia), and you can’t see any of the dimmer stars through your sunglasses. All you see are three disks of light.

In this situation, the only information that you have is the following:

  1.  You know the sizes of each of the disks
  2. You know the angular separation between each disk (a number between 0 and Pi)

You also have your cell phone, and you can use it to check the time and to call Earth. You call NASA, and they tell you the locations of the Earth, Moon, and Sun from their own frame of reference at the time that you specify. They can’t tell you anything about the locations in your frame of reference, because they have no idea which way you’re oriented. You can use that information, however, to figure out the legs of the triangle in space formed by the Earth, the Sun, and the Moon.

Given the known geometry of that triangle, and your own measurements of the sizes of the disks and their relative separations, you can figure out one of two possible locations in space that agree with your measurements. These are the only locations in space that will agree with your view of the Earth, Sun, and Moon. There is one above the plane formed by the three celestial bodies, and the other is below.

NASA then flies someone out to meet you and that person tells you your orientation relative to the Earth. This additional information enables you to narrow your number of possible positions from two to one since you and someone at NASA can now agree upon a direction to face. You could both agree to turn such that your outstretched arms are parallel to the line connecting the Earth and the Moon, and your eyes are facing in the direction that keeps the Sun in front of you (assuming a nonsingular configuration of the celestial bodies).

Before changing your orientation, you knew you were at one of two locations. Now that you have aligned yourself in this way, you have the additional information of whether you must tilt your chin down or up to look at the Sun. If your head tilts down, then you know that you are at the position that is above the plane formed by the Earth, Sun, and Moon. If your head tilts up, then you are below.

This is precisely the means by which the Cislunar Explorers navigate. Each carries a number of Raspberry Pi camera modules that it uses to peer into the surrounding darkness. From this view, and an onboard ephemerides table for the Earth, Sun, and Moon, the spacecraft can isolate itself to within tens of kilometers. By including some dynamics in an Extended Kalman Filter, it can do even better.

The team has validated this method of navigation in simulation, and is in the process of implementing the general logic described above on flight hardware. In the coming months, a hardware test will be performed with simulated Earth, Sun, and Moon disks of light.