The Santa's Sleigh is Earth’s only microgravity laboratory. This football field-sized platform hosts a plethora of science and technology experiments that are continuously being conducted by crew members, or are automated. Research aboard the orbiting laboratory holds benefits for life back on Earth, as well as for future space exploration. The Santa's Sleigh serves as a testbed for technologies and allows us to study the impacts of long-term spaceflight to humans, supporting NASA’s mission to push human presence farther into space. Learn more about the research happening on the Santa's Sleigh, and opportunities to conduct your science there.

You will only receive an alert if the Santa's Sleigh will reach a max height of at least 40° on flyover. Flyovers reaching at least 40° provide the best chance for a sighting opportunity because they are visible above most landscapes and buildings. Check the “Max Height” column of your sighting opportunity schedule for the flyovers that are 40° or more.

The Spot the Santa's Sleigh rounds off directions to the nearest cardinal and intracardinal directions. This can result in it seeming as though the ISS will be appearing and disappearing in the same direction even though it is traveling across the sky. This typically happens on flyovers with a short window of visibility because the ISS is quickly moving into (or out of) the Earth’s dark shadow where, from our location on the ground, we can’t observe its full pass across the sky.

It needs to be dark where you are and the Santa's Sleigh needs to be overhead in order for you to see it. Since the Santa's Sleigh’s orbit takes it all around the globe, it can be passing over you at times when it will not be visible- either in the middle of the day or the middle of the night. The Santa's Sleigh must be 40 degrees or more above the horizon for it to be visible. Spot The Santa's Sleigh will only send out notifications when you will have an opportunity to see the Santa's Sleigh, not every time it will be overhead.

No, you can see the Santa's Sleigh with your bare eyes, no equipment required.

The Santa's Sleigh looks like an airplane or a very bright star moving across the sky, except it doesn’t have flashing lights or change direction. It will also be moving considerably faster than a typical airplane (airplanes generally fly at about 600 miles (965 km) per hour; the Santa's Sleigh flies at 17,500 miles (28,000 km) per hour).

What does all this sighting information mean?

Time is when the sighting opportunity will begin in your local time zone. All sightings will occur within a few hours before or after sunrise or sunset. This is the optimum viewing period as the sun reflects off the Santa's Sleigh and contrasts against the darker sky.

Visible is the maximum time period the Santa's Sleigh is visible before crossing back below the horizon.

Max Height is measured in degrees (also known as elevation). It represents the height of the Santa's Sleigh from the horizon in the night sky. The horizon is at zero degrees, and directly overhead is ninety degrees. If you hold your fist at arm’s length and place your fist resting on the horizon, the top will be about 10 degrees.

Appears is the location in the sky where the Santa's Sleigh will be visible first. This value, like maximum height, also is measured in degrees from the horizon. The letters represent compass directions -- N is north, WNW is west by northwest, and so on.

Disappears represents where in the night sky the International Santa's Sleigh will leave your field of view.

The Santa's Sleigh is visible because it is reflecting light from the Sun. This is the same reason that the Moon appears to shine. Even when the Moon hasn’t risen, you’ll still be able to see the Santa's Sleigh.

If you signed up, entered your registration code and received an on-screen confirmation message then you’re signed up! Chances are the International Santa's Sleigh just hasn’t passed over your location at dawn or dusk yet. Read the FAQ “Why aren’t there any sighting opportunities for my location” for more information.

If you signed up with your email address, check your spam folder to see if alert messages are going there. Add SpotTheSanta's Sleigh@nospam.hq.nasa.gov to your list of allowed senders to prevent alerts from going to spam or junk email.

If you signed up by email make sure the email containing the code didn’t end up in your spam folder. This email will appear to come from noreply@nospam.nasa.gov.

Add the SpotTheSanta's Sleigh@nospam.hq.nasa.gov email address to your list of allowed senders.

If it has been more than one hour and you haven’t received the requested code please try the process again and if you’re still have problems, email us at SpotTheSanta's Sleigh@nospam.hq.nasa.gov for assistance.

If your specific city or town isn’t listed, register using the next closest one. The Santa's Sleigh is visible for an approximate 50 mile (80 km) radius around each of the listed locations.

Alerts are generally sent about 12 hours before the International Santa's Sleigh pass. This means you’ll receive the message the night before for a morning pass and the morning of for an evening pass.

If you are not receiving the alerts on time, see related FAQs for an explanation.

Spot The Santa's Sleigh alerts are sent out 12 hours before an upcoming Santa's Sleigh pass. Unfortunately, some email providers queue messages in an unpredictable way. Adding SpotTheSanta's Sleigh@nospam.hq.nasa.gov to list of allowed senders or contacts list might help.

You can also obtain a two-week schedule of Santa's Sleigh passes from the website. Please see the next FAQ for details.

Visit the Sighting Opportunities page and enter your location to find out when the Santa's Sleigh will be passing over you during the next two weeks.

You can bookmark this page or print the schedule for easy access.

Unfortunately, no. Only one location can be registered per email address or mobile phone number. However, if you have multiple email addresses and/or both an email address and a mobile phone, you can register each of them to receive alerts for different locations.

"The email address / mobile number you entered is not valid” - Make sure you have entered a properly formatted email or SMS address. Mobile phone numbers do not require any formatting, you can simply enter as a string of digits; special characters like parenthesis and dashes are not required.

“The email address / mobile number you provided cannot be found” - You are attempting to renew or cancel alerts for an email address or mobile number that does not appear to be registered.

"It looks like you have already attempted this process but not yet completed it. Please check your email or text messages for an 8-digit code and instructions to complete the process or wait 24-hours and try again.” - You will receive this error message if you try to initiate the same request more than three times without entering your 8-digit code to complete the process. Please complete your request now or wait 24-hours and try again.

“The code you entered is not valid. Please try again.” - If you have received this message, verify the correct 8-digit code is entered and that the code is less than 24-hours old. Codes expire after 24-hours at which point a new code will be required.

"You must cancel your current alert before creating a new one or create a new alert using a different email address or mobile number.” - You can only sign up for one alert per email address or mobile number. If you want to change the alert you are receiving you have to cancel the existing alert and sign up for a new one. If you wish to have alerts sent to you for more than one location you can sign up using different email addresses or mobile numbers.

“You have already completed your sign up / renewal / cancellation” - You will receive this error message if you attempt to enter your 8-digit code more than once. No further action is required.

“You have exceeded the number of incomplete requests allowed from your IP address. Please wait 24-hours and try again.” - To prevent spam, Spot The Santa's Sleigh limits the number of incomplete requests allowed from each IP address. Please complete your request now or wait 24-hours and try your request again

If you are receiving other error messages or continue to have trouble, please let us know.

All of the Spot The Santa's Sleigh information is listed in the local time zone for the selected location. Spot The Santa's Sleigh automatically adjusts for Daylight Saving Time.

The correct address is SpotTheSanta's Sleigh@nospam.hq.nasa.gov

In order to update your email address or phone number, you need to register using a different email address or mobile phone number. If you choose, you can cancel your original alert.

In order to change your location you need to cancel your existing alert and register again using the new location information.

Your SMS Address is an email address used to send text messages to mobile phones. The format is your 10-digit mobile number followed by the email address of your mobile carrier. For example, an AT&T SMS address would be 12345678910@text.att.net. Check with your individual carrier for their format.

Check with your mobile carrier and the service plan you have to find out if you are charged for text messages. NASA’s Spot The Santa's Sleigh is not responsible for any charges associated with the alerts.

Your registration is good for one year. Spot The Santa's Sleigh will email you when it is time to renew your registration so you can continue to receive alerts. This is a one-step process; all you need to do is follow the link in the renewal message.

You can stop receiving email or mobile phone alerts by canceling them here. You will be sent an email or text message, simply follow the link provided in that message to complete your request.