Press Release
May 26, 2023
ispace, inc.

ispace Announces Results of the "HAKUTO-R" Mission 1 Lunar Landing
Landing Anomaly Identified for Future Mission Improvements
TOKYO—May 26, 2023—ispace, inc., (ispace) a global lunar exploration company, announced
today that it has reviewed and completed the analysis of the flight data from its HAKUTO-R
Mission 1 landing sequence on April 26, 2023. The flight data was obtained by operations
specialists at ispace’s Mission Control Center in Nihonbashi, Tokyo.
The analysis reveals that the lander fully completed the entire planned deceleration process,slowing to the target speed of less than 1 m/s in a vertical position at an altitude ofapproximately 5 kms above the lunar surface. Although the lander did not complete a softlanding, the cause has been identified and improvements are being incorporated into Mission 2and Mission 3.
On April 26, 2023, at 00:40 Japan Standard Time, the lander began the descent sequence froman altitude of approximately 100 kms above the lunar surface. At the end of the planned
landing sequence, it approached the lunar surface at a speed of less than 1 m/s. The operation
was confirmed to have been in accordance with expectations until about 1:43 a.m., which was
the scheduled landing time.
During the period of descent, an unexpected behavior occurred with the lander’s altitude
measurement. While the lander estimated its own altitude to be zero, or on the lunar surface, it
was later determined to be at an altitude of approximately 5 kms above the lunar surface. Afterreaching the scheduled landing time, the lander continued to descend at a low speed until thepropulsion system ran out of fuel. At that time, the controlled descent of the lander ceased,
and it is believed to have free-fallen to the Moon's surface.
The most likely reason for the lander’s incorrect altitude estimation was that the software did
not perform as expected. Based on the review of the flight data, it was observed that, as thelander was navigating to the planned landing site, the altitude measured by the onboard
sensors rose sharply when it passed over a large cliff approximately 3 kms in elevation on thelunar surface, which was determined to be the rim of a crater. According to the analysis of theflight data, a larger-than-expected discrepancy occurred between the measured altitude value
and the estimated altitude value set in advance. The onboard software determined in error thatthe cause of this discrepancy was an abnormal value reported by the sensor, and thereafter thealtitude data measured by the sensor was intercepted. This filter function, designed to reject analtitude measurement having a large gap from the lander’s estimation, was included as a robust
measure to maintain stable operation of the lander in the event of a hardware issue including
an incorrect altitude measurement by the sensor.

One major contributing factor to this design issue was a decision to modify the landing site
after critical design review completed in February 2021. This modification influenced theverification and validation plan despite numerous landing simulations carried out before thelanding. ispace as the mission operator maintained overall program management responsibility
and took into account the modifications in its overall analysis related to completing a successful
mission. It was determined that prior simulations of the landing sequence did not adequately
incorporate the lunar environment on the navigation route resulting in the software misjudging
the lander’s altitude on final approach.
The analysis reveals that the cause of the lander's failure to make a soft landing was due to thesoftware, especially in the phase just prior to landing. This information will be incorporated into
software design, as well as upgrades and expansion of the scope of preparatory simulations of
the landing sequence for our future missions, including Mission 2 and Mission 3, to improve theaccuracy of landing sequences.
Based on the fact that communications will not be reestablished with the lander, it has beenconcluded that the completion of the Mission 1 Milestones Success 9 (completion of the lunarlanding) and Success 10 (establishment of stable conditions after landing), could not be
achieved, and customer payloads could not be operated after the landing.
“Mission 1 demonstrated a great deal of technical reliability, as our lander reached the lunar
surface just prior to landing. Now, we have been able to identify the issue during the landing
and have a very clear picture of how to improve our future missions. While it is unfortunatethat we were not able to fully meet the expectations of all our stakeholders, including ourcustomers, all of us at ispace are proud of what we accomplished in Mission 1 and are very
positive about what we can accomplish,” said Takeshi Hakamada, Founder and CEO of ispace.
“We have already begun work on Mission 2 and Mission 3. We are prepared to face thechallenges and make every effort to improve. We will ensure that the valuable knowledge
gained from Mission 1 will lead us to the next stage of evolution. We believe that this is ourcommitment and our duty to all our stakeholders. ‘Never Quit the Lunar Quest’ In this spirit, wewill continue to move forward.”
During Mission 1 the HAKUTO-R lunar lander completed Success 1 through Success 8 of theMission 1 milestones. The lander was able to withstand the harsh mechanical environment ofboth the launch and deployment phases without sustaining damage to any of its elements. It
then withstood a lengthy deep space cruise demonstrating its flight readiness. In addition, thelander performed well through multiple orbit control maneuvers, indicating that it can beoperated in Mission 2 using the same Series 1 model as in Mission 1, without the need for any
major modifications. The thermal design, communications, and electric power demonstratedfunctionality as planned, and based on analysis of the flight data, a more efficient operation canbe achieved in Mission 2. At this time, there are no changes to the launch schedule for Mission
2 (scheduled for 2024) and Mission 3 (scheduled for 2025).

Mission 1 Milestones#Milestone

Success Criteria per Milestone

1Completed

Completion of Launch
Preparations••2Completed

Completion of Launchand Deployment••

3Completed

4Completed5Completed

6
Completed

Establishment of a
Steady Operation State(*Initial CriticalOperation Status)
Completion of firstorbital control
maneuver•

Completion of stabledeep-space flight
operations for one
monthCompletion of all deep
space orbital control
maneuvers before LOI•••

Complete all development processes of the Series 1 lunar lander
before flight operations.
Contract and prepare launch vehicle, and complete integration oflunar lander into the launch vehicle.
Complete successful separation of the lunar lander from the launchvehicle.
Prove that the lander’s structure is capable of withstanding the harshconditions during launch, validating the design and gathering
information towards future developments and missions.
Establish communication link between the lander and Mission
Control Center, confirm a stable attitude, as well as start stable
generation of electrical power in orbit. The completion of this step
verifies the integrity of lander core systems and customer payloads.
Complete the first orbital control maneuver, setting the lander on acourse towards the Moon and verifying operation of the main
propulsion system, as well as related guidance, control, andnavigation system.
Prove that the lander is capable of steady deep-space flight bycompleting a nominal cruise and orbital control maneuvers over a 1
month period.
Complete all planned deep space orbital control maneuvers by
utilizing gravity assist effects and successfully target the 1stlunar orbit
insertion maneuver. This stage proves the ability of the lander’s deepspace survivability, as well as the viability of ispace’s orbital planning.

7Completed
8Completed
9
Incomplete
10
Incomplete

Reaching the lunar
gravitational field /lunar orbit
Completion of all orbit
control maneuvers inlunar orbit
Completion of lunar
landing
Establishment of asteady system state
after lunar landing

•

•••
•

Complete the first lunar orbit insertion maneuver and confirm thelander is in a lunar orbit, verifying the ability of ispace to deliver
spacecraft and payloads into stable lunar orbits.
Complete all planned lunar orbital control maneuvers before thelanding sequence.
Confirm the lander is ready to start the landing sequence.
Complete the landing sequences, verifying key landing abilities for
future missions.
Establish a steady telecommunication and power supply on the lunar
surface after landing to support customer payloads' surface
operations.

About ispace, inc.
ispace, a global lunar resource development company with the vision, “Expand our Planet.
Expand our Future.”, specializes in designing and building lunar landers and rovers. ispace aims
to extend the sphere of human life into space and create a sustainable world by providing highfrequency, low-cost transportation services to the Moon.
The company has offices in Japan, Luxembourg, and the United States with more than 200
employees worldwide. ispace technologies U.S., inc. is part of a team led by Draper, which wasawarded a NASA Commercial Lunar Payload Services (CLPS) Program contract to land on the far
side of the Moon by 2025 (as of September 2022). Both ispace, and ispace EUROPE S.A. (ispaceEU) were awarded contracts to collect and transfer ownership of lunar regolith to NASA, andispace EU was selected by ESA to be part of the Science Team for PROSPECT, a program whichseeks to extract water on the Moon.
Established in 2010, ispace operated “HAKUTO” which was one of five finalist teams in theGoogle Lunar XPRIZE race. The company’s first mission, part of its HAKUTO-R lunar exploration
program, launched on Dec. 11, 2022, from the United States on a SpaceX Falcon 9 rocket andcompleted 8 of 10 mission milestones. Subsequent missions are in development with launches
expected in 2024 and 2025. ispace has also launched a lunar data business concept to support
new customers as a gateway to conduct business on the Moon.
For more information, visit: www.ispace-inc.com; Follow us on Twitter: @ispace_inc.
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