NASA PVT+ vs PeakPal
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
NASA PVT+
This app provides a validated tool for conducting psychomotor vigilance tests, crucial for sleep, alertness, and performance research. It offers multiple study frameworks, including simple tests, basic multi-day studies, and specialized aviation research protocols.
- Psychomotor Vigilance Test (PVT)
- Karolinska Sleepiness Scale (KSS)
- Sleep Diary
- Simple PVT mode
- Basic Study framework
- Aviation Study framework
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The official NASA PVT+ (Psychomotor Vigilance Test) is a validated iOS based touchscreen PVT that includes multiple industry standard research forms for collecting a wide range of research data for sleep, alertness and performance studies. The app has three principle data collection schemes designed to accomidate a wide range of research studies. The Simple PVT: The Simple PVT is a single presentation of the Psychomotor Vigilance Test (PVT; described below). Participants can be instructed to take a PVT at any time. There is no limit to the number of PVTs that a participant can take. Basic Study: The Basic Study provides a single or multiday pre-set framework for collecting research data. Participants are prompted to complete a sleep diary after their main sleep episode. The participant is then prompted to complete three PVT and Karolinska Sleepiness Scale (KSS) responses during the day. The participants also complete a sleep diary before bed. Aviation Study: The Aviation Study provides a multiday pre-set framework for collecting aviation related research data. Split into Off-Duty Days and Duty Days. Participants are prompted to complete a sleep diary after their main sleep episode. The participant is then prompted to complete three PVT and KSS responses during off-duty days. On duty days, the participant is prompted to complete a PVT and KSS pre- and post-duty. They are also prompted to complete a PVT, KSS, hassle factors, use of fatigue countermeasures, and inflight rest at the top of descent for each flight. The participants also complete a sleep diary before bed. The number of flights within a duty day can be adjusted. The aviation study also includes a pre-study baseline questionnaires that can be completed at study enrollment. The specific components of the application include: - Psychomotor Vigilance Test (PVT): A simple reaction-timed test that is sensitive to sleep loss and circadian misalignment. The PVT displays a box on the screen and participants are instructed to tap the screen with their dominant thumb when a millisecond counter appears in the box and begins to count up. After the participant taps the screen, the counter briefly displays the reaction time in milliseconds, then the counter disappears, and the participant is instructed to refrain from touching the screen until the next millisecond counter appears in the box. The counter appears randomly every 2 to 10 seconds. The PVT can be configured by the investigator to the desired duration (currently validated for a 5-minute test). - Karolinska Sleepiness Scale (KSS): The KSS is a self-reported sleepiness rating where the participant is asked to rate their level of sleepiness within the last five minutes on a scale from 1 to 9. - Sleep Diary: The Basic Study and Aviation Study each include a sleep diary that the study participant is prompted to complete at the beginning and at the end of the main sleep episode. The pre-sleep sleep diary asks the participant to record any naps that were taken prior to the main sleep episode, along with indicating the time of bedtime. The post-sleep sleep diary asks the participant to record the time that it took to fall asleep, number and duration of night awakenings, final wake time, and a sleep quality rating. - Study Enrollment Information: The Aviation Study includes a demographic questionnaire and the Morningness-Eveningness Questionnaire along with a practice sleep diary and practice PVT to orient the participant to study procedures. Data collected from study participants using the NASA PVT+ iOS application does not include Personally Identifiable Information (PII). Research data is never collected directly by NASA unless a volunteer is participating in a NASA study. Data collected for research studies conducted outside of NASA, through use of the NASA PVT+ application, is never sent to NASA without a specific agreement between the outside organization and NASA.
PeakPal
Measure the height of distant objects and the angle of slopes using your iPhone's camera and motion processor. This app helps identify the highest point on a mountain, assess avalanche risk with color-coded slope angles, and track climbing steepness. It's designed for backcountry enthusiasts by an experienced Alaskan peakbagger.
- Height comparison of distant objects
- Slope angle measurement
- Avalanche risk assessment (30-45 degree slopes)
- Data-embossed summit photos
- Cloud height comparison
- Developed for backcountry travelers
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PeakPal is a backcountry height comparison and slope angle measurement camera app. The iPhone motion processor is used along with the camera to compare the height of a distant object. PeakPal can be used as a simple "mountain climbing advisor". Determine if you are on the highest point of a mountain. Prove you were on the highest summit by taking a PeakPal, data-embossed photo. Determine if you are on a slope that might avalanche (angle text background turns red if slope between 30 and 45 degrees). Know how steep the slope is that you are climbing (or running, if you are a mountain runner). See if incoming clouds are higher or lower than you. This app was developed by an Alaskan peakbagger for backcountry travelers. Decades of climbing and decision making in Alaska's mountains led to the development of this iPhone app.
Screenshots
Verdict
The clearest difference is review sentiment: PeakPal at 100% against NASA PVT+'s 25%. PeakPal also leads on rating (5.0 vs 4.8). NASA PVT+'s advantage is price (Free vs $1.99) and update cadence (every 3 months vs every 10 months). On ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
NASA PVT+ is free to download; PeakPal costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
PeakPal holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: NASA PVT+ has 10 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 25% of NASA PVT+'s written reviews are positive against 100% of PeakPal's.
NASA PVT+ ships an update every 3 months, PeakPal every 10 months. Both last shipped on November 2, 2026.
| Parameter | NASA PVT+ | PeakPal |
|---|---|---|
| Price | Free — better | $1.99 |
| Rating | 4.8 (10 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 25.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 10 — better | 1 |
| Update frequency | Every 3 months — better | Every 10 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.6 — better | 15.6 |
| Further details — not scored | ||
| Size | 31 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | NASA | Timothy Kelley |
Customer experience
NASA PVT+
PeakPal
In-app purchases
NASA PVT+
No in-app purchases
PeakPal
No in-app purchases









